Detach Font_System, Font_Sprite and Font_Vector from Font.  Font now acts like Font_System
Add loading of sprites onto a font
Add support of spaces in loading fonts via sprites
Implement loading of Font Sprites using resources
Remove FontSystem and FontSprite
Hook the Font_Vector functions back
Modify XMLDisplayCache::load_font() to accept all font resource types
Allow all font resource types (not just sprite!)
Add loading of ttf fonts via resources
Rename Font_Vector to VectorFont, since it is no longer a part of clan::Font