Removed net.cpp's dependency on init.h.

Added explicit include of main.h in init.cpp, changed include of init.h to include of main.h in net.cpp.

Added function registration for net.cpp in init.cpp's network initialization.

TODO: Remove main.h include in net.cpp.
Eliminated protocol.cpp's dependence on main.
Created core.h/core.cpp, started moving core structures from main to core beginning with COutPoint.
Moved CInPoint to core. Removed GetMinFee from CTransaction and made it a regular function in main.
Removed AcceptToMemoryPool method from CTransaction. This method belongs to the mempool instance.

Removed AreInputsStandard from CTransaction, made it a regular function in main.
Moved CTransaction::GetOutputFor to CCoinsViewCache.

Moved GetLegacySigOpCount and GetP2SHSigOpCount out of CTransaction into regular functions in main.

Moved GetValueIn and HaveInputs from CTransaction into CCoinsViewCache.

Moved AllowFree, ClientCheckInputs, CheckInputs, UpdateCoins, and CheckTransaction out of CTransaction and into main.

Moved IsStandard and IsFinal out of CTransaction and put them in main as IsStandardTx and IsFinalTx. Moved GetValueOut out of CTransaction into main. Moved CTxIn, CTxOut, and CTransaction into core.
Moved CCoins, CTxOutCompressor, CTxInUndo, and CTxUndo to core.
Removed script.cpp's dependence on main.h
Moved UpdateTime out of CBlockHeader and moved CBlockHeader into core.
IsDust takes minimum fee parameter.
CTxMemPool::accept requires a NULL parameter at the end if last parameter not used.
UpdateTime, GetLegacySigOpCount fix.
CheckInputs, CheckTransaction fix.
CCoins constructor calls fix.
CScriptCheck constructor calls fix, use tx.vin instead of vin in CheckInputs.
viewTemp -> view fix.