Added lib files
Merge branch 'develop/graphics_driver' of github.com:tinyx/xv6_graphics into develop/graphics_driver

Conflicts:
	Makefile
Prepare to revert
Fix the layer buffer problem
Draw line function is now working correctly
Print text working correctly
Finish the drawing polygon funtion
Merge branch 'master' into develop/graphics_driver

Conflicts:
	Makefile
Mouse Arrow added
Merge branch 'test/mouse_driver' into develop/mouse_interact

Conflicts:
	Makefile
Mouse now could interact with the graphics
Merge branch 'test/mouse_driver' of github.com:tinyx/xv6_graphics into develop/mouse_interact
Now mouse could partially refresh the layer, which is much more
effecient
drifting tweak