Added/Modified/Moved... (check description)

- Added goal to herd sheep to in minigame5
- Changed sheep logic in minigame5
- Added lives in MainMenu and game over condition in WinLoseScreen
- Added gameoverscreen texture
- Added howtominigame1/3/5 textures
- Modified minigame 1, 3 & 5 to have the same constructor parameters and
similar tutorial screens as minigame 2, 4 & 6
- Moved textures for minigame 1, 3 & 5 to textures/topdownminigame/