Merge pull request #194 from bvssvni/master

Upgraded to latest Rust
Merge pull request #195 from bvssvni/master

Made all_widgets example runnable from top level
Merge pull request #197 from bvssvni/master

Added SDL2 to .travis.yml
Merge pull request #199 from bvssvni/master

Upgraded to latest opengl_graphics
Merge pull request #200 from bvssvni/master

Upgraded
Merge pull request #201 from bvssvni/master

Using `Text` from piston-graphics
Update command to build and run examples
Merge pull request #206 from yuripourre/master

Update command to build and run examples
Fixed example link
Upgraded to latest shader_version