Fast Movement detection & drag

[graindcafe]

Hello,

There is a problem with the fast movement detection when the zoomType is set to "drag" (not tested with others).
Passing the mouse over the zoomWindow make the lens go to center ("lens.setcenter") instead of doing nothing.

We can show that in test pages, but adding "console.log("fast movement detected");" after the test (line 148 in version 2.3) will confirm that the problem came from this test.

You may attach & detach the mousemove function when clicking