This implements `hover`, `pointer`, `any-hover` and `any-pointer` and
the values `course`/`fine` (pointer) and `hover`.
A best effort is made to get capabilities from the system but if unknown
always falls back to assuming a mouse is present.
Vim control lines were re-introduced or not entirely cleaned up.
This nukes them again.
Removing from accessible, [root], tools, uriloader, widget, xpcom and
xpfe.
Resolves#1656