Fix bug where dock leaves gap near edge of display returning from lock screen.

DETAILS:
The issue only happens when dash-to-dock is set to fixed position and workspaces-to-dock is
set to autohide on with intellihide off. What causes the issue is the layout manager updating
the work area while the dock is animating.

OTHER NOTES:
A second issue observed while testing was that  workspaces-to-dock failed to update the
thumbnails size when set to fixed position and returning from lock screen.

A third issue observed while testing was that workspaces-to-dock failed to update the
thumbnails size when dash-to-dock was set to fixed position.

All issues are dealt with in this commit.
Fix bug where the window count only works if the taskbar is present.
Gap fix in commit 0ee53213ca53aadc6a3bc6813a7833f183bc8bb0 is inconsistent. Rework
code to trigger workarea region update during initialization.
Accommodate Gnome 3.12+ change: Use Meta.later_add instead of Mainloop.idle_add function.
Update readme, metadata, and installation zip for Gnome 3.12 v26.