Cherry-pick: Legacy graphics support

Tweaks to make the game run on older systems
* Switch project API from HiDef to Reach

* Make background 1024x1024 (was 1000x1000)

* Draw menu screen differently from ingame screen, since there were a lot
  of non-power of two textures there and I didn't have time for anything
  more complicated.

Conflicts:

	spacePirates/SpacePirates/Game1.cs
	spacePirates/SpacePirates/Level.cs
	spacePirates/SpacePiratesContent/SpacePiratesContent.contentproj
Fix drawing of sprites/fonts on some systems

Spritesorting mode was changed from BackToFront to Immediate.