Added scale snap settings to 2D

Created by: MCrafterzz

It feels really strange that there are snap options for movement and rotation but not scaling so I implemented it. This is defently an improvement that should exists in the editor and would be useful for everyone. It also leads to more consistency which is always welcome. Let me know what you think (maybe there's a reason why no one has implemented this yet).

As it's quite a small improvement and not a giant feature I didn't create a issue in proposals, should I?