Margin not remembered per file

[Stefan]

When setting the margin on the file scope in Options Editor Lite, it will be applied and the File-column correctly reflects the value.
But on restarting Cud, this value will be replaced with the User value.

Not important. I don't really need to set different margins per file. It was more or less by chance that I discovered this bug. No need to fix it now or any time soon.

[main Alexey]

It was easy to add, so I added this; will be in update.