Have Renderer::draw take the batch by-value
Make batch creation consistent
Clean up batch stuff in gfx/lib.rs
Remove variant re-exports
De-stutter ShaderModel variants
Demonstrate how to use lib without gfx::Graphics
Clean up warnings
Merge pull request #471 from bjz/cleanups

API cleanups and other assorted changes
Have `Render::draw` take batch by reference

`OwnedBatch` broke with
https://github.com/bjz/gfx-rs/commit/1b36d71172c6a9a16154158734e7b68396c
81476
Merge pull request #472 from bvssvni/fixdraw

Have `Render::draw` take batch by reference