Make dialogcontainment appear above the main containment, but as a black transparent overlay.
neat effect to show that there is a modal dialog.
make pluginloader return 0 if it doesn't need to load our non-plugin components.
it'll now also return our engine (if need be, and if it was already created), else it will return a new one.

without this, I'm thinking if multiple sections attempted to physically get the same engine/service, we'd have problems.
make the shutdown dialog respond to authenticationenabled.

Fix incompatible inconcistencies in authentication{Enabled,Completed}. looks like I hadn't renamed all of the uses of it.
Fix DialogContainment not being created (as per kdelibs changes).
We create it ourselves, directly, now. (w/out kdmpluginloader).