Moved WriteToDisk from main.h to main.cpp
Moved CBlock::ReadFromDisk out of CBlock to functions in main.h
Moved ReadFromDisk implementation to main.cpp
Pulled DisconnectBlock out of CBlock.
Pulled ConnectBlock out of CBlock.
Pulled AddToBlockIndex out of CBlock.
Pulled CheckBlock out of CBlock.
Pulled AcceptBlock out of CBlock.
Moved CBlock from main.h to core.h