styles - Update bootstrap-switch to use bootstrap 3 template

Update bootstrap-switch to 2.0.0
fix - Stop flicker that happened when switching attendance status

The bootstrap-switch kept flickering while changing the switch status.
That was because of calling the render method each time the state
changed.

The solution for this is to call render() only once during initialization.
Callbacks are already in place to update state to server when
bootstrap-switch's status changes.