make some fixes
Change clickOnChechBox index
Added a workaround for the solo.clickOnText method
Probable fix for testRenameCurrentProjectViaActionBar
Refactor to isCheckBoxChecked
Added a tryCount for longClickOnTextInList if Robotium looses the list
Probable fix for testImageCache
Added asserts for testRenameProject to check wether the currentProject stays the same after renaming
Probable fix for testImageCache
Fix BroadcastBricksTest
Merge pull request #391 from Catrobat/fixing_testcases

Fixes #387 
Fixes #390
Fix deleting of unused broadcast messages
Merge branch 'master' into DeleteBroadcastMessages