Add initial implementation of 2-handle range sliders for integers.
Add float implementation of range widget
Add an extended range abbreviation including a step value
Fix format problem when showing an error
Add some tests for the 4-5 int/float form in interact()
Adjust range style so that the vertical range marker is visible
Compiled changes to minified CSS
Remove 4-5 tuple forms from interact()
Fix validate logic if min/max are changed
Remove tests for 4-5 tuples, add tests for validate logic
Merge branch 'master' into interact-range-widgets

Conflicts:
	IPython/html/static/style/ipython.min.css
	IPython/html/static/style/style.min.css
	IPython/html/static/widgets/js/widget_int.js
Default to 25-75% of min-max if no value is set instead of 0-1
Support both value tuple and upper, lower traits for both int and float widgets
Add a number of extra tests for the range widgets
Merge master
Remove a rogue print statement
Merge master
Remove errant tabs from js
Change `range` trait to `_range`
Test case for setting only lower or upper, no sensible default so should be an error