Merge pull request #492 from bvssvni/master

Changed `SourceRectangle` to use `i32`
Merge pull request #493 from bvssvni/master

Implemented `AddBorder` for `EllipseContext`
Merge pull request #494 from bvssvni/master

Implement `AddBorder` for `RectangleBorderContext`
Merge pull request #495 from bvssvni/master

Implemented `AddBorder` for `RoundRectangleContext`
Merge pull request #496 from bvssvni/master

Implemented `AddBorder` for `EllipseColorContext`
Merge pull request #497 from bvssvni/master

Implemented `AddBorder` for `RectangleColorContext`
Merge pull request #500 from bvssvni/master

Implemented `AddBorder` for `RoundRectangleColorContext`
Merge pull request #501 from bvssvni/master

Implemented `AddBorder` for `BevelRectangleContext`
Merge pull request #502 from bvssvni/master

Implemented `AddBorder` for `BevelRectangleBorderColorContext`
Merge pull request #503 from bvssvni/master

Added methods on `RelativeSourceRectangle`
Merge pull request #504 from bvssvni/master

Added `flip_hv` to `RelativeTransform2d`
Merge pull request #505 from bvssvni/master

Updated to latest Rust-Empty
Changed buffer sizes in `stream_polygon_tri_list_xy_f32_rgba_f32`

Closes https://github.com/PistonDevelopers/rust-graphics/issues/506