Added client API & prototypal GUI.
GUI & network stuff.
Vaguely working single-instance client.
Basic client.
Fixes & additional functionality in the network stack.
Doesn't crash on peer dropout.
added pthread to cmake
Avoid socket info timing issues by keeping a copy of the info handy for
cross-thread replies.
Merge pull request #5 from xeroc/master

added pthread to cmake
Network functionality improved, code somewhat dirty now though.
Move to vitalik's PoW...
Vitalik's diff changes.
Move to obscure's Hello format.
Back to how it was.
Log output.
Move to agreed network format.
GetChain fix.
Slightly more error resistant.
Peer discovery just-about safe, though you'll end up with a lot of
peers.
DONE: Connect default should be drop-down and populated via web api.