Add Angular.js usage example
Add Angular.js usage example

closes #83

Jonekee/screenfull.js,mcanthony/screenfull.js,sindresorhus/screenfull.js,Jonekee/screenfull.js,utter-step/screenfull.js,mcanthony/screenfull.js,minamagdy666/screenfull.js,minamagdy666/screenfull.js,utter-step/screenfull.js,andrew168/screenfull.js,andrew168/screenfull.js,microlv/screenfull.js,sindresorhus/screenfull.js,microlv/screenfull.js,sindresorhus/screenfull.js