We explicitly set a parent. We can't assign to
ApplicationWindow.transientParent though, only to
Window.transientParent, so we just call setTransientParent in C++.

There are probably a few things wrong with this, but I'm going to call it good enough for an initial commit

Also fix a lot of warnings.

This is so viewing profiles from the invite dialog will work as expected.

This fixes binding loops and gives it a (in my opinion) sane size.