Issue #1129 - Fix for Transaction Malleqbility

This patch creates a hard fork where signature format becomes far more
strict than SSL strictly allows.   It depends upon a recent update to FC
which allows optional strict checking of signatures.

Conflicts:
	libraries/blockchain/include/bts/blockchain/checkpoints.hpp
	libraries/blockchain/include/bts/blockchain/fork_blocks.hpp
checking for transaction uniqueness based upon timestamp and digest
Merge branch 'develop' of https://github.com/BitShares/bitshares into develop
fix regression