remove errors from ppcutil.go
Peercoin PoS metadata management
Merge branch 'master' of https://github.com/mably/btcchain into mably

Conflicts:
	ppcutil.go
Code cleaning
error fixing, lot of TODOs, tests passed
Merge branch 'master' of github.com:mably/btcchain
Use new method to fetch header and meta from database
Merge branch 'master' of https://github.com/mably/btcchain

Conflicts:
	chain.go
Use peercoin specific ppcNewBlockNode in CheckConnectBlock
removed GeneratedStakeModifier and StakeEntropyBit from Block.Meta
Merge branch 'master' of github.com:mably/btcchain
Merge branch 'master' into mably
Merge branch 'master' of https://github.com/mably/btcchain into mably
getPrevNodeFromNode seems to return nil for some blocks