Removed references to normalized tx id.

 * Still need to handle txid mutations
Added more logic for doublespends. Added logic for mutations

 * Now handling mutated tx ids. Just creating a new payment object.
Added support for mutations, doublespends, and reorgs

 * Invoice's payment history now displays doublespends and reorg data
 * New status was added for comfirmations = -1, "invalid"