[Expo] Make thumbweel workspace-scroll more predictable.

And, you no longer have to pointing at a thumbnail to be able to use
the scroll wheel.
[Window Manager] Started on a simple ignore-window feature.

Currently, ignored windows are not ignored completely, only
if they are on another workspace.
[Alt-Tab] Try to handle when pushModal fails.
[Expo] Don't let accidental middle-mouse-click delete workspace in the middle of scrolling.
Add gir1.2-gtkclutter-1.0 to runtime dependencies (for cinnamon-settings)
Fix failure to comma