Fixed some warnings after rust update.
Re-export some GLFW event enums in sb6 lib.

The samples should be abstracted from GLFW.
Get Windows build working and update README.md

Using http://github.com/bitshifter/glfw-rs until Windows fixes are
applied upstream. Updated README.md with Windows build instructions
based on the instructions for building Rust on Windows.
Imported shader files from OpenGL SuperBuble repo.

The original files are from
https://github.com/openglsuperbible/sb6code/tree/master/bin/media/shaders
Makefile build now copies shaders to target/media
Updated README build and run instructions