Treat non-final transactions as non-standard
Port from Bitcoin: 6f8730752cf92ff8269812c01a6d9d35fff82e75
Rename CTransaction.IsFinal to .IsFinalTx
as in Bitcoin
Remove dead transaction replacement code
Port from Bitcoin: 98c7c8fd1d3712e02be0e9f2eeca7e02aa54d197
Merge pull request #159 from phelixnmc/IsFinal_nonstandard

Treat non-final transactions as non-standard