Window scaling partial fix

Main:
-renamed WIDTH -> TARGET_WIDTH
-renamed HEIGHT -> TARGET_HEIGHT

window:
-locating window moved to Initialise()
+to match window creation
-now tries to select a window size based on supported resolutions
+should scale x/y to a preset, and the other to match the ratio
+should ensure best screen coverage, as long as less than target

-should return correct width property for anything that uses it e.g. GUI
setup
-as far as I can tell, the mouse errors were caused by losing aspect
ratio. This should no longer happen.

!does not attempt to scale in-game resources, positions etc.
-e.g. images, internal waypoints