Clear current line on ctrl-C

cmd/geth, jsre: restore command line editing on windows

eth, trie: removed key prefixing from state entries & merge db fix

support for user agents

core/vm: fixed jit error & added inline docs

Fixed database merge strategy to use the correct database. Due to a copy
paste fail when doing type evaluation the same database was being
iterated (chain), all others were ignored.

Removed state prefixing because {H(code): code} is stored in the same
database as the rest of the state.

p2p: validate recovered ephemeral pubkey

rlp: boolean support

p2p: fix value of DiscSubprotocolError

cmd/geth: remove spaces in client identifier

We had the wrong value (12) since forever.

PR #856 broke command line editing by wrapping stdout with a filter that
interprets ANSI escape sequences to fix colored printing on windows.
Implement the printer in Go instead so it can do its own
platform-dependent coloring.

As a nice side effect, the JS console is now noticeably more responsive
when printing results.

Fixes #1608
Fixes #1612

p2p/discover: fix two major bugs in reply packet handling

web3: updated

cmd/ethtest: added trace flag for debugging

If the timeout fired (even just nanoseconds) before the deadline of the
next pending reply, the timer was not rescheduled. The timer would've
been rescheduled anyway once the next packet was sent, but there were
cases where no next packet could ever be sent due to the locking issue
fixed in the previous commit.

As timing-related bugs go, this issue had been present for a long time
and I could never reproduce it. The test added in this commit did
reproduce the issue on about one out of 15 runs.

Table.mutex was being held while waiting for a reply packet, which
effectively made many parts of the whole stack block on that packet,
including the net_peerCount RPC call.

opNumber did not create a new big int which could lead to the block's
number being modified.

core, eth, trie, xeth: merged state, chain, extra databases in one

cmd/utils, core: disable exp diff for olympic net

cmd/geth, core/vm: setup vm settings and defaulted JIT disabled

core/vm: jit vm

string version for build server

xeth: fixed contract addr check

cmd/geth, eth: added canonical extra data

web3: regression. Fixes #1613

Reduced big int allocation by making stack items modifiable. Instead of
adding items such as `common.Big0` to the stack, `new(big.Int)` is
added instead. One must expect that any item that is added to the stack
might change.

Reduced the amount of state copied that are required by N calls by doing
a balance check prior to any state modifications.