Slider fixes and enhancements.

- follows HTML5.1 input range specification as it possible.
- handles input/change events

Fixes #10 Slider: add missing intern tests (unit + functional)
Fixes #32 Slider: the 'disable' state should have an associated style
Fixes #90 Slider: unable to change width
Fixes #30 Slider: properties must be dynamic as much as possible
Fixes #29 Slider: a way to translate the range interactively
Fixes #130: Slider: use templates
Fixes #131
Migration from delite/Invalidating to decor/Invalidating.

decor/Invalidating is now included by delite/Widget, so it shouldn't be
referenced explicitly.

Refs #134.
fixes related to decor/Invalidating change,
fixes #134 more or less
Fixes for recent decor/Invalidating changes, fixes #185.
stop using deprecated watch() method,
and various other fixes, refs #134
remove test_Slider.html, fixes ib;-js/deliteful#186
fix wrong comma
update Slider to new Invalidating, fix dojo deps in Rule
Button.js update for Stateful#observe().