Brush up shaders about light-show-boilerplate

[richies-dev]

Removed unused shaders, revised vertex shaders (aside from particle, but that will be done in #23) and cleaned some fragment shaders. Still need to finish touching up:

• point-light-depth-map.geom
• phong-diffuse-specular.frag
• phong-color.frag
• floor-shader.frag

[richies-dev]

See commit: 609c2dd

This will be added to the backlog. I need to study a bit more on using two lights along with two shadow maps and verify the order I should be doing things.