Multiple main window support, and action-collections

[David Nolden]

I've tried fixing the multiple main window support. The problem is that 
additional mainwindows contain none of the plugin actions, and thus are nearly 
useless.

The plugins manage their actions through KXMLGuiClient, and when adding the 
actions using that interface to additional main windows, all the actions are 
removed from the standard main window. One KXMLGuiClient can only contribute 
to one main-window as it seems.

So it seems like the current design is incompatible with multiple-main-window 
support.

Now I'm thinking about adding something like
"virtual KXMLGUIClient* 
IPlugin::createActionsForMainWindow(Sublime::MainWindow* window)"

Where each plugin has to create a new KXMLGUIClient, fill it with actions, and 
return it. Essentially the same thing that plugins do in their constructor 
now.

Ideally then, IPlugin would not be based on KXMLGUIClient at all, since that 
is not compatible with multiple-main-window support.

What do you think?

Greetings, David