unhexlify txid into a buffer-compatible object
unhexlify txid into a buffer-compatible object

fixes #59

gotcha/testcounter,tokenly/counterparty-lib,Paytokens/paytokensd,patricklodder/dogepartyd,Tetchain/tetchaind,Ziftr/counterpartyd,Reddcraft/reddcraftd,F483/counterparty-lib,paytokens-beta/paytokensd,Bluejudy/bluejudyd,Litetokens/litetokensd,Tetchain/tetchaind,Dogeparty/dogepartyd,monaparty/counterparty-lib,monaparty/counterparty-lib,CounterpartyXCP/counterparty-lib,Bluejudy/bluejudyd,Metronote/metronotesd-alpha,jarymoth/counterpartyd,coinwarp/dogeparty-lib,Ziftr/counterpartyd,CounterpartyXCP/counterparty-lib,stefcrypto/counterparty-lib,F483/counterparty-lib,ClearingHouse/clearinghoused,Reddcraft/reddcraftd,ClearingHouse/clearinghoused,Dogeparty/dogepartyd,Peertokens/peertokensd,metronotes-beta/metronotesd,Czarparty/czarpartyd