Make platform and render modules free-standing crates and make gfx a facade
Merge pull request #70 from bjz/facade

Make platform and render modules free-standing crates and make gfx a facade
Added initial support for different shader languages.

Instead of a `&[u8]` or `Vec<u8>`, shaders are now represented by a
`ShaderSource` type that can contain different shader source
languages. The device then selects the right one at runtime.
Merge pull request #72 from Kimundi/compat_gl_shader

Added initial support for different Shader languages.
Hacky legacy OGL compat