Touch: Add mobile tests for 'reversed' slider

[jespirit]

The mobile touch tests which can be found in test/specs/TouchCapableSpec.js only cover a few of the basic/common scenarios. It would be helpful, in particular, if someone could add tests for the reversed option where the slider values are in reverse order. You would also have to consider the orientation (horizontal, vertical) as well as single or range sliders ("range" meaning you have a lower and upper handle which you can control). See Example 4 for an example.

[yuansheng1989]

I would like to do it.