Pre Fontfix-pull commit

 + changed images
 + extended sceneManager.removeObject() assert conditions
 + Created open issues excel
Merge branch 'master' of https://github.com/ErPanfi/ProjectHCI
Font fix encapsulated
Merge branch 'master' of https://github.com/ErPanfi/ProjectHCI
Implemented hourglass and game start countdown

Added excel of open issues