Short form public addresses

Both:

P2PKH

https://en.bitcoin.it/wiki/Transaction#Pay-to-PubkeyHash

and

P2SH

https://en.bitcoin.it/wiki/Pay_to_script_hash

This is covered in BIP0016 and BIP0013, so will need to be own library.

https://github.com/bitcoin/bips/blob/master/bip-0016.mediawiki
https://github.com/bitcoin/bips/blob/master/bip-0013.mediawiki

