Added environment module. Cleaned up compile warnings.
Implemented Environment mutation methods and signals
Implemented the basic environment shortcut construction
Implemented actual uniform binding using the environment shortcut
Uniform blocks and raw buffers support implemented
Added buffer usage enum. Implemented environment variables safety checks.
Refactored environment shortcut construction and verification. Implemented uniforms semantic matching.
expose IndexSlice
Merge pull request #44 from photex/master

ignoring .dir-locals.el
Merge pull request #45 from csherratt/index_slice

expose IndexSlice
Merge branch 'envir' of https://github.com/kvark/gfx-rs into kvark-envir

Conflicts:
	src/gfx/lib.rs
Merge branch 'kvark-envir'
-Add nicer error prints when the Environment errors out.
-Fix a typo ValueI32Vec instead of ValueF32Vec
Merge pull request #47 from csherratt/bug_fixes

Minor bug fixes found during testing.