When attempting to paste very long lines of text the REPL goes
completely fubar, never completing the paste. Removing the multiline
support "fixes" this.

Long lines of text are usually pasted when deploying contracts and as it
stands right now makes creating new contracts from the REPL impossible.

eth/downloader: fix header download limiting

Fixes #2201

Godeps, eth, tests: update ethash, used shared for testing

eth/downloader: bump the download queue size to prevent starvation

Closes #2241: Use Keccak-256 from golang.org/x/crypto/sha3 and mention explicitly

p2p/discover: NTP sanity check clock drift in case of expirations

ethdb: fully disable metrics if not requested (oops?)

Added Vagrantfile so that developers can spin up a VM to build geth

eth: fixed homestead tx check

eth/downloader: fix partial rollback and ancestor lookup

core/state, trie: add node iterator, test state/trie sync consistency

As we aren't really using the standarized SHA-3

This hash function is slightly different from the standarized NIST SHA-3
as both of them use different domain separation bits.

Revision: 1f22c0103821b9390939b6776727195525381532

When a block is queried for retrieval we should add a check whether the
block falls within the frontier rules. If we'd always use `From`
retrieving transaction might fail. This PR temporarily changes
everything to `FromFrontier` (safe!).

core, core/vm: consensus changes necessary for the homestead release

console: seed random number generator

p2p, p2p/discover: EIP-8 changes

Assuming the following scenario where a miner has 15% of all hashing
power and the ability to exert a moderate control over the network to
the point where if the attacker sees a message A, it can't stop A from
propagating, but what it **can** do is send a message B and ensure that
most nodes see B before A. The attacker can then selfish mine and
augment selfish mining strategy by giving his own blocks an advantage.

This change makes the time at which a block is received less relevant
and so the level of control an attacker has over the network no longer
makes a difference.

This change changes the current td algorithm `B_td > C_td` to the new
algorithm `B_td > C_td || B_td == C_td && rnd < 0.5`.

* Removed some strange code that didn't apply state reverting properly
* Refactored code setting from vm & state transition to the executioner
* Updated tests