Move mouse to regain manual control in web library not just desktop app

[1j01]

It will have to work a little differently because on the web I have to use events (not query the current mouse position), whereas on the desktop I have to query the current mouse position (and don't have any mouse movement event available.)
I should at least share the timing constants, which may become configurable later.

This isn't as important as in the desktop app, but without this, in a drawing program like JS Paint, it jitters back and forth between the system mouse position and the head tracking mouse position, if you try to draw something with the mouse.