crypto/secp256k1: verify recovery ID before calling libsecp256k1

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.

cmd/geth, cmd/utils: surface the light KDF flag to the CLI

rpc/api: fix #1972 api regression (nil eth panic) in attach

event/filter: fix data race in the test

eth: fix error casting regression during database open

cmd/geth: fix recover command crash if no param is supplied

whisper: fix datarace in expiration test

jsre: fix #1876, sleep too short on a slow test server

tests: fix data race in bad-block-report disabling during tests

eth/downloader: fix dysfunctional ignore list hidden by generic set

eth, p2p, rpc/api: polish protocol info gathering

accounts/abi: ABI fixes & added types

Infinite loop in filters

crypto/secp256k1: add C compiler flags for pkgsrc

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

miner: synchronise start / stop

This PR fixes an issue where the remote worker was stopped twice and not
properly handled. This adds a synchronised running check to the start
and stop methods preventing closing of a channel more than once.

eth: added new testnet peers

cmd/geth, cmd/utils, eth: group CLI flags by purpose

Godeps: upgrade github.com/huin/goupnp

Changed field `input` to new `inputs`. Addad Hash and Address as input
types.

Added bytes[N] and N validation

Fix for xeth OOM issue