* [DEV-105] use utxodiff in mempool instead of utxoview
* [DEV-105] get rid of utxoview
* [DEV-105] fix tests to use utxoset
* [DEV-105] remove utxoview type
* [DEV-105] move DagSetup to test_utils.go
* [DEV-105] add comments and add blockdag/test_utils_test.go
* [DEV-105] add restoreInputs arg to removeTransaction
* [DEV-105] give more descriptive names to vars
* [DEV-115] close txChan outside of HandleNewBlock
* [DEV-105] rename DagSetup -> DAGSetup