Added:
-Icons for window, ALT+TAB view, taskbar, a.s.o.
-A gold chest at the very last room
-A preference helper
-A enum for tiles
-A GOLD boolean in the object controller

Fixed:
-Stairs
-Player spawning in other levels than the first one
-GUI object positions
-Adding entities whilst updating

Changes:
-The color of various texts
-Doors are now gold chests
-Implemented the tile enum in many places
-Room generation now also generates gold chests

And many more changes / additions / fixes
Also cleaned up the code!