remove warning visible_private_types
Make examples depend on rsfml

This caused problems, when invoking make with multiple build processes, because
it would try to build the examples before the rsfml build had been finished.
Merge pull request #30 from aepsil0n/examples_makedep

Make examples depend on rsfml
fix warning + fix build on last master

- warnings -> field begining with cap.
- build -> ICE on trait with default method with not named unused params.