Multiple changes (dir lights, obj fix, warnings)

Added first section of directional light pass to enable skybox with/and
ambient lighting.
Added fix for .obj loading when no normals are present. (for now
produces no normals. Calculation will be implemeneted at a later date.)
Convert degree rotation to Radians for backend. This removes deprecated
code usage of GLM.
Removed swizzle (unneeded) from MD5Animation. This allows upgrade to
newest version of GLM. No bugs found post-upgrade