execute a script from the look and feel package when
an applet is added, adding to the script environment
"applet" that wraps the currently added applet and
"containment" that wraps its containment.
from there the javascript part can do anything it can do
in the startup script as well.
In case of containments, "applet" and "containment" will
be the same thing
REVIEW:125562
if the l&f package has a default layout script, make it win over the one of the shell.
this should be used for distributions to customize.
since there can be one l&f package with multiple shells, a layout is specific for a particular shell package, so search the files as layouts/shellName-layout.js, like layouts/org.kde.plasma.shell-layout.js
REVIEW:121119
Reviewed by: Rohan Garg <rohangarg@kubuntu.org>
Marco Martin
Montel Laurent
Aaron Seigo