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.
This is a low-priority init function that should not be called with
immediate dispatch to the current thread, for performance reasons.
Additionally, do not call RegisterDragDrop for hidden windows.
Since these are just interpreted comments, there's 0 impact on actual code.
This removes all lines that match /* vim: set(.*)tw=80: */ with S&R -- there are
a few others scattered around which will be removed manually in a second part.