Add shaders documentation
Add shaders documentation

printedheart/philogl,printedheart/philogl,shelsonjava/philogl,Drakesinger/philogl,shelsonjava/philogl,shelsonjava/philogl,senchalabs/philogl,printedheart/philogl,Drakesinger/philogl,philogb/philogl,philogb/philogl,philogb/philogl,Drakesinger/philogl,senchalabs/philogl,shelsonjava/philogl,senchalabs/philogl