Remove active blocks from State.
Remove vector of Cell* pointers from State.
Misc cleanup.
State no longer uses any pointers.
Remove guard cells.
No longer enforce ordering on block connection list.
Refactored connection removal in Block.
Add Board::GetConnection() function to access connection carriers.
State uses boost::scoped_arrays instead of vectors.
Reordering of functions in board.cpp.
Renamed SharedLiberties to Carrier.
Replace all GetCarrier calls with GetConnection.