server: Fix QueryTree

The names of properties here were wrong.
wm: Use thinner borders for the window frame
demo: Make xeyes look more like the original

Tweak the drawing slightly
demo: Make the border a little darker
demo: Add a simple menu button

This will eventually pop up a full menu
demo: Make the panel allocate the full height to the widgets

This means that the "Menu" button can be prelit with the full
height.
demo: Add a dummy menu window that opens on click
demo: Remove the need to map the window explicitly

Clients now do this on connect time.
demo: Remove some of the simple wrapper utility functions

Most of them are blatantly uninteresting.
Remove background color entirely

I've tried a few times to fix it, but I think ultimately it's just
too hard to shoehorn into the canvas drawing model.

Which is an absolute shame.

Goodbye backgroundColor, you will be missed :(
demo: Use generic 'monospace' for the terminal font

Rather than an explicit font reference that may not exist.
wm: Make sure to not drag if the user didn't click directly on the frame
Move the server and WM to subdirectories of src/
demo: Split all the clients into their own files
wm: Make sure to redraw the window when focus changes
server: Add debug region redraw code

To visualize redraws
server: Remove a bad comment