Updated gemfile with git repos.
Change Gemfile git repos to point to our forks.
Merge pull request #4 from hybridgroup/bug-variadic-params

Updated gemfile with git repos.
Make OS specific binding maps

Change joystick drivers for ps3 and xbox360 controllers to use OS
specific binding maps for buttons and axis.
Xbox, not XBox
46-joystick
Merge pull request #7 from hybridgroup/artoo-docs

Artoo docs/commands & events
Merge pull request #6 from mikejford/os-controller-mapping

OS/driver based controller mapping implementation
Remove mikejford's version of ruby-sdl-ffi

Keeping reference to GitHub version of hybridgroup-ruby-sdl-ffi for now, since
changes it contains are required for artoo-joystick to work correctly, and
haven't yet been pushed to RubyGems.
Add install directives for libsdl to travis ci
Correct directive for jruby in travis ci
Reorganize install instructions in README
Update dependencies incl. hybridgroup-ruby-sdl-ffi
Bump Artoo dependency to 1.6.0
Update to version 0.4.0
Resolve merge conflicts