Make negative object scale impossible (via an option)

When using the scale tool/mode it's very easy to set an object to negative scale. This is almost never intended and so often has unwanted negative consequences.

It would be better if, by default, blender would not allow negative scale of objects. When you pass the mouse though the object scale could stay positive.

I think clamping at 0 would be frustrating.

This could be an option so people could have the old behaviour back if they wanted.

Note this is only for object mode, it's fine and often useful to perform negative scaling in edit mode.