No longer use TouchScroll by default on touch devices

TouchScroll can still be used voluntarily by mixing it in after List or Grid.
Add TouchScroll test page
List: remove remaining TouchScroll logic
Refactor the selector column plugin into a mixin
Move documentation from the GH wiki into the repo.
Update Selector documentation
Fix indentation of Selector.html
Selector: Fix doc indentation
Refactored the Selector mixin to fix a bug related to multiple columns and to move more functions into the prototype so they can be overridden.  Also incorporated fixed for #822.