Save preferences per file

[TwistedLincoln]

It would be very handy if the preferences could be separated into global and per-file categories. For example, checking for updates and the catalog view should clearly be global, but other settings (particularly new wall dimensions and floor thicknesses) should be linked to each home file instead.

I have several projects, each of which have different wall sizes. With the current system, I have to remember to adjust the default preferences each time I switch files. When I forget, I often find that I've drawn several walls that are much taller or shorter than the rest of the plan, which I don't notice until I look at the 3D view.