Delete unused broadcast messages upon save project
Fix BroadcastBricksTest
Fix deleting of unused broadcast messages
Merge branch 'master' into DeleteBroadcastMessages
Fix test
Merge branch 'master' into DeleteBroadcastMessages
Merge branch 'master' into DeleteBroadcastMessages
Merge branch 'master' into DeleteBroadcastMessages
Merge pull request #401 from Catrobat/DeleteBroadcastMessages

Delete broadcast messages