* common/math: optimize PaddedBigBytes, use it more

name              old time/op    new time/op    delta
PaddedBigBytes-8    71.1ns ± 5%    46.1ns ± 1%  -35.15%  (p=0.000 n=20+19)

name              old alloc/op   new alloc/op   delta
PaddedBigBytes-8     48.0B ± 0%     32.0B ± 0%  -33.33%  (p=0.000 n=20+20)

* all: unify big.Int zero checks

Various checks were in use. This commit replaces them all with Int.Sign,
which is cheaper and less code.

eg templates:

    func before(x *big.Int) bool { return x.BitLen() == 0 }
    func after(x *big.Int) bool  { return x.Sign() == 0 }

    func before(x *big.Int) bool { return x.BitLen() > 0 }
    func after(x *big.Int) bool  { return x.Sign() != 0 }

    func before(x *big.Int) int { return x.Cmp(common.Big0) }
    func after(x *big.Int) int  { return x.Sign() }

* common/math, crypto/secp256k1: make ReadBits public in package math

* common: remove CurrencyToString

Move denomination values to params instead.

* common: delete dead code

* common: move big integer operations to common/math

This commit consolidates all big integer operations into common/math and
adds tests and documentation.

There should be no change in semantics for BigPow, BigMin, BigMax, S256,
U256, Exp and their behaviour is now locked in by tests.

The BigD, BytesToBig and Bytes2Big functions don't provide additional
value, all uses are replaced by new(big.Int).SetBytes().

BigToBytes is now called PaddedBigBytes, its minimum output size
parameter is now specified as the number of bytes instead of bits. The
single use of this function is in the EVM's MSTORE instruction.

Big and String2Big are replaced by ParseBig, which is slightly stricter.
It previously accepted leading zeros for hexadecimal inputs but treated
decimal inputs as octal if a leading zero digit was present.

ParseUint64 is used in places where String2Big was used to decode a
uint64.

The new functions MustParseBig and MustParseUint64 are now used in many
places where parsing errors were previously ignored.

* common: delete unused big integer variables

* accounts/abi: replace uses of BytesToBig with use of encoding/binary

* common: remove BytesToBig

* common: remove Bytes2Big

* common: remove BigTrue

* cmd/utils: add BigFlag and use it for error-checked integer flags

While here, remove environment variable processing for DirectoryFlag
because we don't use it.

* core: add missing error checks in genesis block parser

* common: remove String2Big

* cmd/evm: use utils.BigFlag

* common/math: check for 256 bit overflow in ParseBig

This is supposed to prevent silent overflow/truncation of values in the
genesis block JSON. Without this check, a genesis block that set a
balance larger than 256 bits would lead to weird behaviour in the VM.

* cmd/utils: fixup import

* vendor: add github.com/btcsuite/btcd/btcec

* crypto: add btcec fallback for sign/recover without cgo

This commit adds a non-cgo fallback implementation of secp256k1
operations.

* crypto, core/vm: remove wrappers for sha256, ripemd160

- Use defined constants instead of hard-coding their integer value.
- Allocate secp256k1 structs on the C stack instead of converting []byte
- Remove dead code

go get github.com/gordonklaus/ineffassign
ineffassign .

To address increasing complexity in code that handles signatures, this PR
discards all notion of "different" signature types at the library level. Both
the crypto and accounts package is reduced to only be able to produce plain
canonical secp256k1 signatures. This makes the crpyto APIs much cleaner,
simpler and harder to abuse.

This commit includes several API changes:

- The behavior of eth_sign is changed. It now accepts an arbitrary
  message, prepends the well-known string

        \x19Ethereum Signed Message:\n<length of message>

  hashes the result using keccak256 and calculates the signature of
  the hash. This breaks backwards compatability!
  
- personal_sign(hash, address [, password]) is added. It has the same
  semantics as eth_sign but also accepts a password. The private key
  used to sign the hash is temporarily unlocked in the scope of the
  request.
  
- personal_recover(message, signature) is added and returns the
  address for the account that created a signature.

This pulls in the assembly implementation of keccakf1600 for amd64.

The account management API was originally implemented as a thin layer
around crypto.KeyStore, on the grounds that several kinds of key stores
would be implemented later on. It turns out that this won't happen so
KeyStore is a superflous abstraction.

In this commit crypto.KeyStore and everything related to it moves to
package accounts and is unexported.

Unlocking the accounts in the test doesn't help with anything.

As we aren't really using the standarized SHA-3

This hash function is slightly different from the standarized NIST SHA-3
as both of them use different domain separation bits.

Revision: 1f22c0103821b9390939b6776727195525381532

* change gas cost for contract creating txs
* invalidate signature with s value greater than secp256k1 N / 2
* OOG contract creation if not enough gas to store code
* new difficulty adjustment algorithm
* new DELEGATECALL op code

The s2 parameter was not actually written to the MAC.

Turns out we actually don't need it, USE_NUM_NONE works
because we also set USE_FIELD_INV_BUILTIN.

thanks to Felix Lange (fjl) for help with design & impl

They cause compiler warnings for people who don't have these
directories. People with pkgsrc can add the directory through CGO_CFLAGS
instead.

The C library treats the recovery ID as trusted input and crashes
the process for invalid values, so it needs to be verified before
calling into C. This will inhibit the crash in #1983.

Also remove VerifySignature because we don't use it.

pkgsrc is a cross-platform package manager that also
supports OS X.

* lines with leading space are ommitted from history
* exit processed even with whitespace around
* all whitespace lines (not only empty ones) are ignored

add 7 missing commands to admin api autocomplete

registrar: methods now return proper error if reg addresses are not set. fixes #1457

rpc/console: fix personal.newAccount() regression. Now all comms accept interactive password

registrar: add registrar tests for errors

crypto: catch AES decryption error on presale wallet import + fix error msg format. fixes #1580

CLI: improve error message when starting a second instance of geth. fixes #1564

cli/accounts: unlock multiple accounts. fixes #1785
* make unlocking multiple accounts work with inline <() fd
* passwdfile now correctly read only once
* improve logs
* fix CLI help text for unlocking

fix regression with docRoot / admin API
* docRoot/jspath passed to rpc/api ParseApis, which passes onto adminApi
* docRoot field for JS console in order to pass when RPC is (re)started
* improve flag desc for jspath

common/docserver: catch http errors from response

fix rpc/api tests

common/natspec: fix end to end test (skipped because takes 8s)

registrar: fix major regression:
* deploy registrars on frontier
* register HashsReg and UrlHint in GlobalRegistrar.
* set all 3 contract addresses in code
* zero out addresses first in tests