Remove the last use of passing width into Dash by having the
Pane with the previews scaling dynamically and relying on
Clutter scaling.
If we only have one workspace, don't display a selection frame
for it.
Rework Dash into a searchArea and sectionArea, which get
explicitly sized by overlay.js. We use the workspaces size
to choose the size of those dash areas.
Switch dash colors/boxes etc. to ones from shell-black02.
Add a gradient to the panel.
Add a magnifier.svg for use in search.
There was lots of fixed positioning in the Panel; now it is completely
dynamic, and width/height is driven from main.js. We still have a
global constant Panel.PANEL_HEIGHT, but this is a big step towards
eliminating it.
Also, this avoids overdraw in the "way too many tray icons" case. The
clock will shift left.
Replace 'overlay' with the more descriptive name 'overview'
where the Activities Overview is meant. Call it Overview
(capitalized) in code comments.
The overlay-group and overlay-key provided by Mutter are not
affected, since they may be used for other components than
the Activities Overview.
