Updated Gamefield so the squares are even sized
Fixed a bug where the MouseCursorSprite wasn't transparent after placing a pupil
Added a new abstraction layer in OOP of Teachers (also planned for pupils but not yet implemented. Also added a new type of teacher: the sport teacher
Deleted some old files out of git repo
Cleared the file history
Updated 'Story_idea.png' and added a new button 'weiter'
Added a temporary image for a concurrency
Cleared the repository of deleted files
Collision Detection works now fine
Added some graphics of chemie & pc teachers plus shots and animation picture for an explosion