fixed (hopefully) sdkmanager self-cast errror, issue #6
improved structure of RoboSpockTest to improve speed & ability to modify at runtime.
made use of previous commit.
added prev commit to CHANGES.md
Travis CI: make it output STDOUT/ERR & stacktraces.
bumped version to 0.3.1
Merge pull request #7 from Centril/sdkmanager_fixissue6

fixed (hopefully) sdkmanager self-cast errror, issue #6 & other improvements...