Elm syntax coloring and formatting for blocks

Elm syntax coloring and formatting for blocks.

As per https://groups.google.com/forum/#!topic/elm-discuss/HIdcbC0IOHk the blocks in Elm, like glsl blocks, are not formatted properly. It would be nice if they were not only syntax colored properly based on the embedded type (for known blocks like GLSL), but potentially even change the atom language within them (like how Atom's markdown auto-colors code fences properly based on the language).

Example GLSL block in a function:

fragmentShader : Shader {} Uniform Varying
fragmentShader =
    [glsl|
         precision mediump float;
         varying vec4 fragColor;

         void main () {
             gl_FragColor = fragColor;
         }
    |]

edubkendo / atom-elm

Elm syntax coloring and formatting for blocks #44