Add plugin system
Add useAllPlugins to allow Leap.loop to use plugin
Bump Version and include version in top of .js file
Bump Version and include version in top of .js file
Merge branch 'plugins' of github.com:leapmotion/leapjs into plugins

Conflicts:
	leap.js
	leap.min.js
	lib/_header.js
Move addWrappedStep in to pipeline
Allow method chaining for connect, use, on, disconnect, setBackground, and loop.
Allow stopUsing for frame-loop based plugins
Add "stopUsing" method for plugins
Add examples/plugins.html
Add changelog
Update README with plugin links
Bump to version 0.4.0
Remove `controller.plugin` method stub
Remove console.log
Update version.js
Merge branch 'master' into plugins

Conflicts:
	bower.json
	leap.min.js
	package.json
Merge pull request #138 from leapmotion/plugins

Add plugin system
Allow controller.use to accept a plugin factory directly, bump to 0.4.1
Added contributors file- apache 2.0 with some signatures