ethclient now returns ethereum.NotFound if the server returns null and
no error while accessing blockchain data.

The light client cannot provide arbitrary transactions. The change to
split transaction access into its own interface emphasizes that
transactions should not be relied on and recommends use of logs.

It should never return null for a known uncle, but even if it does
we can't just crash.

* Filter refactoring
* API tests added + bugfix
* fixed the error logs
* FilterID fixed
* test cases fixed
* key generation updated
* POW updated
* got rid of redundant stuff

ethstats: check if received event is valid

cmd/geth: tidied up the source

ethstats: don't drop concurrent head reports (mini forks)

node: improve error handling for web3_sha3 RPC method

* miner: removed unnecessary state.Copy()

* eth: made use of new miner method without state copying

* miner: More documentation about new method

cmd: drop DAO related choice flags since ETC diverged

ethstats: report block miner, gas limit and gas consumption

* cmd/bzzd: add missing p2p/discovery flags
* cmd/bzzd: fix two bugs crashing bzzd if bootnodes flag given
* cmd/bzzd: make no swap default, renamed flag bzznoswap->bzzswap
* internal/web3ext: correct methods for bzz IPC module
* cmd/bzzd: ethapi param not mandatory. Warning if no blockchain
* cmd/bzzd: correct default IPC modules in help string
* cmd/utils: fix help description for networkId - add Ropsten
* cmd/bzz, swarm/api, swarm/network: add swarm networkId flag
* cmd/bzzd: change nosync flag to sync and BootTFlag

Improve hex encoding/decoding

build: use single CocoaPods package, pre-release dev builds

common.Address JSON encoding now enforces the 0x prefix, but key files
don't have the prefix.

The new package is purpose-built to handle the encoding consumed and
produced by the RPC API.

Fixed unwinding of bad hashes when already on the canon chain

accounts: disable file system watcher on windows