modifications to sliders & slider test

- some work on the constructor and properties, most properties still need comments though.
- draw parameter is now an element not a jquery selection object.
- added a top level span w/ a class matching current convention - widgetSlider.
- changed the identification of component elements to use class and element rather than id.
- use the format function passed in for the readout.

in the sliderTest.html, see the format specified for test 5 which uses the unicode "figure space" to keep the readout from changing size and causing everything to move as you slide.