rpc: several fixes and support for optional arguments

rpc: be less restrictive on the request id
rpc: improved documentation
console: upgrade web3.js to version 0.16.0
rpc: cache http connections
rpc: rename wsDomains parameter to wsOrigins

cmd/geth: add JS preload parameter

Update ethash

cmd/utils: bugfix where database is opened multiple times

console: use transaction output formatter for eth.pendingTransactions…

accounts/abi/bind: support generating bindings for various arrays

rpc: use go-winio instead of vendoring a named pipe implementation

RPC pub sub

core, miner: remove Frontier canary

abi: support for input and output slices & removed support for implicit type conversion

p2p: enable EIP-8 handshake sending

cmd/utils, miner: A/B testing JIT VM. Disabled for miners

cmd/geth: add missing gas target flag (fixing 0 convergence issue)

With the Ethereum Homestead fork is now behind us, we can
assume that everyone runs an EIP-8 capable client.

cmd/geth: fix startup with empty database

This prevents display of the warning for --dev and --olympic.

accounts/abi/bind: surface raw wrappers to access low level ops

common: added Hash unmarshal json length validation

This PR introduces a 10% probability that you'll run the client with the
JIT enabled testing the new client and helps us potentially catch
errors when reported.

This feature is **disabled** for miners (disabling the JIT completely).
The JIT can however be force for miners if they enable both --jitvm and
--forcejit.

eth: enforce signing hashes using eth_sign instead of arbitrary data

core: homestead chain configuration & artificial gas floor target mining flag