Fix #154
Don't break scrolling when 'special key to move windows' is disabled.
Fixes linuxmint/Cinnamon#3334
Revert some inadvertant changes from a previous commit:

https://github.com/linuxmint/muffin/commit/38bcd77e2dabc5abf912f3eee389fc4988fc0b89
Ensure steam notifications appear over the panel.
Fixes #2357

I'd prefer to simply move the popup into the work area, but for
for some reason, I can't apply our tooltip fix to these popups -
with tooltips, we check if they're overlapping and move them to a
better spot.  These popups I cannot seem to move.

It seems like Steam is using the monitor geometry to calculate the
position for this popup.  I think it would be more appropriate to
get the primary monitor's *work area* which is the monitor geometry
minus any struts (panels, other items to be considered part of the
DE's chrome) - this would return the usable workarea where any
calculation should take place within.  Note that doing this could
end up eliminating the need for DE hacks in Steam's code, as well
as ours.
Remove special handling of the overlay key.  It will be just a normal applet
keybinding.
Port all keybinding schemas to cinnamon-desktop, allow all keybindings to use
arrays of bindings
Update some dependencies
Add "osx" click-to-focus mode.

- Requires cinnamon-desktop wm schema update.
- Clicking on a window focuses and raises it, but does not
  pass the button click event to the window.

Extra notes, questions:
- Haven't tested thoroughly...
- testing, more testing...
- enable mode by:
     gsettings set org.cinnamon.desktop.wm.preferences focus-mode 'osx'
- escape it via cinnamon settings
- still needs cinnamon patch for settings
osx-mode: Handle programs like multi-window gimp in the same way
as click-to-focus mode, but only within the gimp toolbox and image
windows.  When switching between multiple image windows, osx focus
behavior is preserved
osx mode: Only apply to primary mouse click