Allow using settings with MSVS backends.

Unless I'm missing something obvious, this is all we need to allow trivial use of settings with the projects.

What bothers me is that there is no way to check that I updated all occurrences of the ctors with the new parameter and I'm not sure if I found all of them (the indirect use of `XmlFormatter` and such doesn't make it easy), please check if I didn't forget something. TIA!