Merge pull request #507 from bvssvni/master

Changed buffer sizes in `stream_polygon_tri_list_xy_f32_rgba_f32`
Merge pull request #509 from bvssvni/master

Upgraded to latest Rust-Empty
Merge pull request #512 from bvssvni/master

Added `stream_quad_tri_list_xy_f32_rgba_f32` to `triangulation`
Merge pull request #514 from bvssvni/master

Fixed potential overflow bug
Added constants to `stream_polygon_tri_list_xy_f32_rgba_f32`

Closes https://github.com/PistonDevelopers/rust-graphics/issues/511