Update Diamond wallet to version 2.0.2

Implement numerous code fixes, correcting calculations and working around blockchain corruption to enable PoS function.
Corrected hash function selection based on coin mechanics.
Improved coin mechanics calculations.
Added long orphan chain fix, borrowed from GalaxyCoin.
Added fixes to the getbalance RPC calls to account for PoS rewards, borrowed from MintCoin.
Fixes in QT UI and initial code cleanup.