Add SDL dependency, pointing to fork dev branch

Also removes deps for {xbox,dualshock}-controller
Remove existing Xbox 360 and DualShock drivers
Update .travis.yml
Update .travis.yml
Start on integrating with node-sdl
The correct SDL class is 'Joystick'
Poll for Joystick events, emit when they occur
Add DualShock 3 controller config JSON
WIP on DualShock 3 driver
Add body of #driver method, improve specs
Use shared Driver class, customized config
Update DualShock3 examples
Update docs
Add Xbox 360 controller mapping
Point to hybridgroup-sdl
Remove use of #fetch, correct references to SDL
Merge pull request #10 from hybridgroup/refactor/use-libsdl

Refactor - Use LibSDL