Capturebuilding fixed, added globalprefab

- fixed bug with capturebuildings. The new building was not created.
Code for that was removed by accident.
- Removed the swipecontroller from the _scripts and added it to the
_GlobalScripts.
- Added the _GlobalScripts prefab to every scene. It will auto destroy
new instances, only one is allowed. Doesn't matter if game is started
from menu or level.
- Fixed bug in level 3 where a position x was 7.90001 instead of 8. The
tile calculation needs these numbers in increments of 2.