This commit fixes issues with toggling on and off Monocle and Floating
Window mode by ensuring that the relevant windows are always at the top
of the Z order, and in the latter case, ensuring that the top visible
window is used to search the local floating window state of the process.
After some experimenting I seem to have been able to adjust to remove
all of the invisible window borders by default, so if desired, a user
can now have no gaps at all.
Also upgraded to the latest version of the windows-rs crate since I saw
it was available. Thankfully no breaking changes.
