block tests only need the chain, not all of ethereum.

This was suggested during review.

Private keys would be locked early if SignLocked was called more than
once because the unlockLater was still running. Terminate it properly.

RWMutexes must be write-locked when writing in order
to actually protect the writes.

There is no point to using time.Duration if the value is interpreted as
milliseconds. Callers should use the standard multiplication idiom to
choose the unit. In fact, the only caller outside of the tests already
does so.

Account is now always a non-pointer. This will be important once
the manager starts remembering accounts.

AccountManager is now always a pointer because it contains locks
and locks cannot be copied.

The account manager is now responsible for picking the
default account and the coinbase.

* Add from to eth_transact / xeth.Transact and add static pass in lieu
  of integrating with native Mist window for user passphrase entry
* Make eth_accounts return AccountManager.Accounts()
* Add a Generate Key menu item in Mist

Improved CLI

Godeps: bump github.com/ethereum/ethash

This fixes the build.

It is now possible to exit the REPL using Ctrl-C, Ctrl-D or by typing "exit".

The ethereum command line interface is now structured using subcommands.
These separate the different tasks it can perform.

Almost all flag names are backwards compatible.

The key tasks have not been ported to subcommands since they will be
replaced by the new accounts infrastructure very soon.

It is no longer imported by any package in our tree.

Various functions throughout the codebase used it to grab settings. This
has to stop because I want to use them without reading the config file.

These functions can now be used without reading the config first:

* ethdb.NewLDBDatabase
* ethrepl.NewJSRepl
* vm.New

Merge branch 'develop_pull_request' of https://github.com/tendermint/ethermint into tendermint-develop_pull_request

Add initial implementation of block tests

* Add blocktest cmd and support for block tests files in
  tests/BlockTests , the launched node does not connect to
  network, resets state with a genesis block from the test file
  and starts the RPC API

It is unused and untested right now. We can
bring it back later if required.

Until chunked frames are implemented we cannot send messages
with a size overflowing uint24.

They got lost in the transition to rlpxFrameRW.