Frontier/blockpool 

- fix status chain map uses common.Hash as key
- add badPeers increment to IncorrectTD errors (forgotten)
- signal head info update to head section process even if parent hash is not in pool (inserted), so that idle timer can be set to nil
- suicideC -> peer.headInfoTimer
- quit -> peer.bestIdleTimer
- and they are properly set from within getBlockHashes and handleSection

Fix link to build instructions in the readme

Conflicts:
	rpc/responses.go

Blocktests are now integrated in cmd/ethereum.

The generic pointer decoder did not advance the input position
for empty values. This can lead to strange issues and even
infinite loops.

Merge branch 'frontier/blockpool' of https://github.com/ethersphere/go-ethereum into ethersphere-frontier/blockpool

Conflicts:
	rpc/api.go

I don't see why we would need two different accessors for a public field.

This makes Value 24 bytes smaller on 64bit systems.

Value.{Encode,Decode} are gone. It implements rlp.Encoder and rlp.Decoder
instead, so Value can be decoded into directly.

This seems to be the last remaining use of it.