Adding a cabal flag for compiling haskoin against testnet
Adding constant networkName
Adding constant defaultPort
JSON instance for Tx
To/From Json Instances for Outpoint, ScriptOutput and Coin
Added Json Instances for TxHash and Word256. Added Tests for ToJson . FromJson = id
Merge pull request #78 from plaprade/master

Adding a cabal flag for compiling haskoin against testnet