Check that mvn is installed and abort if not

Change-Id: I6f9e78672c361871defe099009c5bd1c58863dab
Closes-Bug: #1276763
Start adding 0.6 release notes

This adds the first release note items.

Change-Id: I41315c671cd11defc7508f1f2af593091adfd557
Merge "Check that mvn is installed and abort if not"
Merge "Start adding 0.6 release notes"