Remove insta-build support.

Leaving it in was a compromise for dealing with the lack of background
building, but now that background building exists, is no longer needed. One
less set of code paths for me to forget to test :).
Remove support for "free" builds.

I never liked  the idea building stuff for free. Another set of code paths
I will no longer forget to test.
Don't enable the settings window for now.

There are no settings to tweak.