Stage dialog stretch button

issues #282 and #313 solved according to https://github.com/Catrobat/DesignAndUsability/blob/master/catroid/Stage/stage_menu_dimensioning.png

testrun:
http://catrobatgw.ist.tugraz.at:8080/job/Catroid-custom-branch-test/914/

testRenameCurrentProjectViaActionBar() fails in current master too.

i didn't touch testRenameCurrentProjectViaActionBar() but it is unstable:
http://catrobatgw.ist.tugraz.at:8080/job/Catroid-single-UI-test/602/
http://catrobatgw.ist.tugraz.at:8080/job/Catroid-single-UI-test/603/

solo.clickOnCheckBox(0) in row 736 sometimes click on the third element
any suggestions?