Change selection area of freehand annotations

Change actionAtPoint() to detect freehand annotations only when the point is over their outline, rather than the bounding box of the annotation. All other annotations are unaffected and are still detected through their bounding box using action->visualGeometry(). This is done do that selection and an erase tool would be more accurate. Do note that as a result, single point strokes cannot be selected, and this is a problem with QPainterPath shape not showing up on a single point @ndavis

Add FreeHandAction::contains() that returns true if the point given lies within the outline of the FreeHandAction annotation's shape.