Since almost all of the callers of shell_app_activate were using the
default workspace (by passing -1), remove that parameter.
Add a new shell_app_activate_full() API which takes a workspace as
well as a timestamp; previously we might have been ignoring event
timestamps from elsewhere.
https://bugzilla.gnome.org/show_bug.cgi?id=648149
Ideally, this would be an entirely-JS implementation, but we have a
couple of issues with gjs and gobject-introspection to work around, so
we need a ShellMountOperation class for the time being.
This first commit implements the show-processes dialog, with a system
modal style very similar to the EndSession dialog.
Implementations of ask-question and ask-password will follow shortly.
https://bugzilla.gnome.org/show_bug.cgi?id=653520
