merge weilu's changes
cleanup throw tests, add case for bad input
remove unused hex helpers
fix spacing
new Opcode() is not used
Merge pull request #53 from coinpunk/base58cleanup

Remove unused hex helpers
Merge pull request #54 from coinpunk/moreaddresstesting

More address testing
Merge pull request #55 from coinpunk/opcodecleanups

new Opcode() is not used