css: Remove unneeded header
css: Disallow bypassing value computation

This special code was added back in the days when computation wasn't
idemptotent. These days it is.

Also, the bypass code path is only used in fallback code that is pretty
much unused.
styleproperties: Remove unused function
styleproperties: Remove header where it's not used
styleproperties: Deprecate
styleproperties: Move into deprecated directory
Fix a problem with screen changes and csd

When a new screen is set on a window, we unrealize it, to
recreate all the resources. But we don't reset the client_decorated
flag, so realize() doesn't call create_decoration() - which makes
sense, since the decoration already exists. But the side-effect
of create_decoration() is to select the rgba visual, and visuals
are per-screen.

Fix this by looking for the rgba visual in set_screen(), and
replacing it with the rgba visual for the new screen, if necessary.
inspector: Use a separate display connection

This helps isolate the inspector from some of the changes that
it can trigger. To specify a different display, set
GTK_INSPECTOR_DISPLAY to the name of the display to use for
the inspector window. If no display is specified, GTK+ will
use a separate connection to the default display.
Fix the build

Some forgotten include path adjustments.