miner, flags: Configurable gas price & log flag change

* --gasprice "<num>" flag
* admin.miner.setGasPrice( <num> )

eth/downloader: prioritize block fetch based on chain position, cap memo...

p2p: more last-minute fixes

This should improve ethereum block propagation times since
we're not not broadcasting blocks to 100% of peers.

With the introduction of static/trusted nodes, the peer count
can go above MaxPeers. Update the capacity check to handle this.
While here, decouple the trusted nodes check from the handshake
by passing a function instead.

p2p: throttled handshakes

Otto.ToValue concurrency error fixed

jsre, cmd/geth: updated web3.js and altered settimeout

Test updates

solidity compiler and contract metadocs integration

xeth, core, event/filter, rpc: new block and transaction filters

Update ethash deps (more build fixes, tests)