rotary dial control via touchscreen is wrong

Controlling a Mixxx rotary dial via currently tested touchscreens is really bad to the point of being almost useless (interestingly, slider controls work fine and as you would expect).

This *might* be because while using a mouse, the cursor is snapped, but a finger controlled cursor is not for some reason? ;-)

This was originally reported in a comment at Bug #1152572, which included (in an attachment) a video demonstrating general responsiveness of Mixxx to a touchscreen, which also showed the dials' unresponsiveness which prompted the filing of this bug.

However, I'd like it if this were *not* considered a child of Bug #1152572, but rather standing on its own as a singletouch bug (that as an added bonus will probably preemptively fix a multitouch bug). As far as I can tell, this bug is the only one that substantially stands in the way of conclusive singletouch facility. If fixed, I think any oldschool monotouch touchscreen will work competently with Mixxx (at least as well as they were meant to work with any program).

It would be encouraging to be able to cross off the list - single touch functionality: dominated. Onward to multitouch.