Uniforms reform
Merge pull request #173 from tomaka/uniforms-reform

Uniforms reform
Fix UniformType type not being accessible and not implementing traits
Merge pull request #178 from tomaka/uniform-type-hidden

Fix UniformType type not being accessible and not implementing traits
Split `Surface` trait between `Surface` and `Framebuffer`
Partially implement Framebuffer for MultiOutputFrameBuffer
Fix tests