Improvements to MoneyManSpec

* Add getTransactionMP and sendToOwnersMP to MastercoinClient
* Deal with “change address problem” in “Send BTC to get MSC/TMSC” test
* Better use of symbolic constants
* etc.
Simple test case of trait with delegate
Bump to Spock 1.0 snapshot and Groovy 2.3.5
Fix missed rename of startCount -> startHeight