do not forget to delete again
The Issue itself should be resolved, Still TODO: Remove Log.d() messages
and write automatic tests, .R import order
Added Test for the Issue, but it fails half of the time due to the 
screenshot not being saved or the thumbnail not loading correctly.
The issue should be resolved with this commit, still debug messages to
get rid of.

Important Change: Had to take the screenshot at the second frame instead
of the first in the render() method of the StageListener, because the
ScreenUtils.getFrameBufferPixels() method used to get the pixels,
returns an all white picture in ~1/5 trys and this was untestable.(And
not intended behaviour)
Cleaned up debug log messages and removed warnings
Temporary framebuffer debug messages inserted
Merge branch 'master' into Update_Screenshot
merged into master, test still not reliable below android 4.0
merged to stay up to date
small cleanup
Merge branch 'master' into Update_Screenshot_2
adapted to formula editor merge
change of screenshot saving to always regenerate the .nomedia file
add programvariable to xmlHeader
acceptance refactoring
Merge pull request #197 from Catrobat/Update_Screenshot_2

Update Screenshot