Enhanced asset and price_feed validation error messages.
Enhanced asset and price_feed validation error messages.

peertracksinc/muse,bigoc/openchain,pmconrad/graphene,oxarbitrage/bitshares-core,abitmore/bitshares-2,bigoc/openchain,cryptonomex/graphene,bitsuperlab/cpp-play2,bigoc/openchain,bitshares/bitshares-2,abitmore/bitshares-2,bitsuperlab/cpp-play2,bitshares/bitshares-2,peertracksinc/muse,pmconrad/graphene,peertracksinc/muse,cryptonomex/graphene,oxarbitrage/bitshares-core,bitsuperlab/cpp-play2,bitshares/bitshares-2,peertracksinc/muse,oxarbitrage/bitshares-core,bitshares/bitshares-2,cryptonomex/graphene,bigoc/openchain,oxarbitrage/bitshares-core,pmconrad/graphene,abitmore/bitshares-2,pmconrad/graphene,abitmore/bitshares-2