Removed useless ChainTrust code
No fees to reward miners in ppcoin
Mint and money supply calculations
GetCoinAge methods
ppc: few fixes and checks
ppc: enforce transaction fees for every block
ppc: checks: wrong coinstake position
ppc: checks: empty coinbase output and coinstake timestamp
ppc: checks: block timestamp and signature
ppc: limited stake duplicity check
Merge pull request #4 from mably/topic/checks_rebase

ppc specific checks