Fix the chainability of on/off method
Rewrite vendor prefix logic
Update Gulpfile
Merge branch 'wip'

Conflicts:
	dist/pin.jquery.js
	dist/pin.jquery.min.js
	dist/pin.js
	dist/pin.lite.js
	dist/pin.lite.min.js
	dist/pin.min.js
Get on a non-existing element returns undefined
Add some draft methods to pin.jquery.js
Debug pin.jquery.js draft and write tests
Build v0.1.3