Merge pull request #2 from bvssvni/master

Added rust-graphics submodule
Merge pull request #6 from bvssvni/master

Added build script
Added information about building

Closes https://github.com/PistonDevelopers/piston-workspace/issues/7
Added information about location of '.rlib' files

Closes https://github.com/PistonDevelopers/piston-workspace/issues/8
Update README.md
Added 'piston-symlinks' to script