* Add member list and settings buttons to spaces

* Un-buttonify the member list button

* Properly button settings *and* members

It seems that you need to manually destroy created objects... Great...

fixes #898

Also fixes some issues where nested transactions will poison the
verification cache.

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

https://doc.qt.io/qt-5/qshortcut.html#mnemonic