Merge pull request #692 from bvssvni/master

Added hex color support
Merge pull request #693 from bvssvni/master

Made `Can` traits specific
Merge pull request #695 from bvssvni/master

Made `Has` traits specific
Merge pull request #696 from bvssvni/master

Implemented `Draw` for `LineColorContext`
Merge pull request #699 from bvssvni/master

Made `Relative` traits inherit `Has` and `Can`
Merge pull request #700 from bvssvni/master

Renamed `RelativeTransform2d` to `RelativeTransform`
Merge pull request #702 from bvssvni/master

Using uniform instead of color per vertex
Merge pull request #704 from bvssvni/master

Replaced deprecated float constants
Merge pull request #709 from bvssvni/master

Added `append_transform`
Merge pull request #710 from bvssvni/master

Added `prepend_transform`
Removed `_xy_f32_rgba_f32` from triangulation module

Closes https://github.com/PistonDevelopers/graphics/issues/711