Support for Glium

[kvark]

This is crazy and detached from reality, but I like speculation :). Possible solutions:

• make a glium backend for Gfx (https://github.com/gfx-rs/gfx-rs/issues/709)
• abstract away Gfx/Glium here in some way
• write a separate high-level abstraction for glium (not my task for sure)

[kvark]

Not happened