Check visibility of the viewhandle

[snooplsm]

If the viewhandle is not visible, dragging should not happen. Also it would be nice if there could be a limit to where one could drag to. Working on that now though.

if (handleView == null)
{
Log.e(TAG, "The view ID " + viewHandleId + " was not found in the RecycleView item");
return false;
}

if(handleView.getVisibility()!=View.VISIBLE) {
return false;
}

[emileb]

Good idea, I've added that for the next release. Thank you!