Merge pull request #27 from xnova/master

Additional testnet fixes with HDWallet

[WIP]
Revert "Merge pull request #27 from xnova/master"

due to broken tests, moved the changes to branch hd-testnet-support

This reverts commit a4ba59e9bacd27191d59959793f8b67eade987c2, reversing
changes made to 36d3d6ebaaa0f99a35c8e0bba765037e006efbc9.
squashed commits from #27
key version check always always relies on the network property

[#27]
HD wallet versions: Bitcoin -> prod, BitcoinTest -> testnet
move address versions into network

Also change address type name:
address_types -> addressVersion
p2sh_types -> p2shVersion
prod -> mainnet
HDWallet prod -> mainnet
throws exception if specified network is unknown

also move network type tests to hdwallet
pull out hdwallet network specific values
Remove String.lpad and cleanup
Add RFC test vectors for convert.bytesToBase64
Rewrite README
Merge pull request #34 from justcoin/readme

Rewrite README
Merge pull request #35 from justcoin/convert-cleanup

Cleanup convert.js and add base64 test
Remove txdb. close #39
Remove EventEmitter.js. close #37
Clean up script.js formatting. ref #41
Simplify Script constructor. close #41
Remove exit node class #32, @abrkn
Remove pailier.js #33, @abrkn