Merge pull request #38 from bvssvni/master

Upgraded to latest Rust
Extracted ease functions as global functions.
Merge pull request #39 from zummenix/master

Extracted ease functions as global functions.
Making ease module as public.
Merge pull request #41 from zummenix/master

Making ease module as public.
Renamed deprecated methods.
Merge pull request #43 from zummenix/master

Renamed deprecated methods.
Use Float and FloatMath #44
Merge pull request #45 from PistonDevelopers/44-fix-float

Use Float and FloatMath #44
Added link to how to contribute

See PistonDevelopers/piston#715
Updating for enum namespacing change