cmd/geth, cmd/utils, eth: added dev mode flag

rlp: precursor changes for trie, p2p

These functions allow destructuring of raw rlp-encoded bytes
without the overhead of reflection or copying.

The bug can cause crashes if Read is called after EOF has been returned.
No code performs such calls right now, but hitting the bug gets more
likely as rlp.EncodeToReader gets used in more places.

core/state: deleted field in StateObject Copy() and unit test

agent/miner Prevent the CpuAgent to be started multiple times

Dev mode enabled some debugging flags such as:

* VM debugging mode
* Simpler proof of work
* Whisper enabled by default
* Datadir to a tmp datadir
* Maxpeers set to 0
* Gas price of 0
* Random listen port

rpc/comms: fix bug attaching the console over http

cmd/geth Autocompletion bugfix which let the console crash

eth/downloader: fix race causing occasional test failure

honors datadir when attaching

fix block time issue

currently, under normal circumstances, you always set the timestamp to previous.Time() + 1.
credits to https://www.reddit.com/r/ethereum/comments/3jcs5r/code_avg_block_time_vs_difficulty_adjustment/cuoi4op

style

Add TestBcForkUncle tests & update JSON files

core: improve block gas tracking

core: Filter on addresses should work as an OR not an AND.

Pull in ethash and go-isatty updates

Fixes build on OpenBSD.

rpc: add receiptRoot to getBlock* responses

build: avoid -X separator warning with Go >= 1.5

Fixes #1679

rpc: return error code for eth_getWork when no work ready

rpc/api allow empty password