fixes #316
Merge pull request #321 from Catrobat/issue#316

fixes #316
vertically center popup
disable user interaction in background

fixes #322
Merge pull request #330 from Catrobat/issue#322

Issue#322
fixed #329
Merge pull request #332 from Catrobat/issue#329

fixes #329
Merge branch 'master' of gh:Catrobat/Catty into issue#323

* 'master' of gh:Catrobat/Catty:
  fixed #329
  disable user interaction in background
  vertically center popup
  fixes #316