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

Exposes some core methods to transition and compute new state
information and adds an additional return value to the transition db
method to fetch required gas for that particular message (excluding gas
refunds from any SSTORE[X] = 0 and SUICIDE.

Fixes #2395

The chain maker and the simulated backend now run with a homestead phase
beginning at block 0 (i.e. there's no frontier).

This commit also fixes up #2388