547 slider bric

@mlippert Slider Ready for code review. (No warning when compiled, except for the sample config).

Implements Slider using Google Closure.
The width configuration is string of format NN{px|%} E.g. : 90%, 200px.
@lbondaryk  I modified the EnergyParabola.html. See if is close to what you want.

Known issues:
- The dragStart and dragEnd events are fired twice.
- Decimal as boundaries does not work.

Not implemented:
- Mark traversed. Possible implementation is to create another div that expands/contracts with the thumb. Whenever the thumb div is moved, the Slider should calculate (on-the-fly) the new size of the traversed area.  Google closure's TwoThumb seems to have this capability already it will have thumbs.
- The Readout that appears on mouse over on the thumb.