Fix displaying of details

Last access now shows "Today <time>" or "Yesterday" or the date
accordingly
Add test for displaying of details
Merge branch 'master' into ShowDetails
Merge pull request #443 from Catrobat/ShowDetails

Show details
Refactor remove unused broadcast messages.
Merge branch 'master' into Refactorazione
Change unused broadcast message set to list.
Change comparison in getPositionOfItem in UserVariableAdapter

After copy ''item'' would be a different object. As we only want to know
the position of ''item'' in the adapter a comparison of the names is
sufficient.
Refactor BroadcastBrick and MessageContainer.
Add broadcast message parameter to BroadcastBrick constructor.
Refactor BroadcastXYZ
Fix selection of ChangeVariableBrick's Spinner after copying a Sprite
Refactor broadcast message engine.
Refactor BroadcastBricksTest
Fix null pointer exception in MessageContainer.getPositionOfMessageInAdapter.
Remove unnecessary set spinner position
Fix testUserVariableSelectionAfterCopySprite
Rename broadcastmessage for compatibility
change some strings in formula editor
FE: further string adaptions