Mouse CB drag resolution

[ustk]

@Christoph-Hart When building widgets out of a panel, the mouse resolution of 1px can most of the time lead to a really poor user experience with rough panel settings...

Of course, one can just divide the drag distance by the mean of a modifier key, but then you lose the sync between mouse cursor and the moving part of the widget.

I dug into juce_MouseEvent but the pixel resolution seems to be deeply baked into the source...

Do you think it's something we could get around?