Issue 645

https://github.com/mastercoin-MSC/omniwallet/issues/645
TransactionGenerationController should only have functionality related to the transaction generation. This function should be defined either within $scope or $scope.walletAssets depending if it's just for the send page or is tu be used on all assets related pages like buy/sell/send/issuance. For the later case, defining this inside the WalletAssetsFormController would be a better Idea.

This is critical for keeping a consistent architecture.