cursors: make spinner in watch cursor rounded, fix hotspots

Apart from making the spinner rounded, I also fixed a bug that made the watch cursor jump around on the last frame in bigger sizes.

I also slightly realigned some other cursors and fixed the wrong cursor being aliased to fleur.

That last one seems to be done on purpose, so using fleur for moving windows is actually an issue with mutter. Fixed here instead.

Okay, it seems like both adwaita-icon-theme and mutter are at fault here. The "fleur" cursor should look like move, not all-scroll. However, the cursor used for moving windows should not be "move", but "grabbing", as that is what "fleur" was aliased to when the mutter code was written.

sigh

TL;DR:

Changed "fleur" to be aliased to "move", changed mutter to use "grabbing" instead of "fleur."