Added more border contexts

Closes https://github.com/PistonDevelopers/rust-graphics/issues/468
Closes https://github.com/PistonDevelopers/rust-graphics/issues/469
Closes https://github.com/PistonDevelopers/rust-graphics/issues/471
Closes https://github.com/PistonDevelopers/rust-graphics/issues/472
Closes https://github.com/PistonDevelopers/rust-graphics/issues/485
Closes https://github.com/PistonDevelopers/rust-graphics/issues/486
Merge pull request #487 from bvssvni/master

Added more border contexts