Merge pull request #8 from bvssvni/master

Added shader module
Merge pull request #9 from bvssvni/master

Added drawing of triangle list
Merge pull request #10 from bvssvni/master

Got triangle working
Merge pull request #11 from bvssvni/master

Quad rendering
Merge pull request #13 from bvssvni/master

Simplified shader by using `DynamicAttribute`
Upgraded to latest opengl_graphics