Panel Plugins: Merge of session-menu/action-buttons/xfswitch functionality

The three aforementioned plugins are very similar/related in functionality, therefore it made sense to merge them into one configurable plugin. So the plugin will have a configurable set of actions, based on the three plugins, and different modes (show as label, show as button), again based on the three plugins.

This is already working code (50%), so not a mockup. Users can select whether they want to show the plugin-actions as action buttons (as seen right to the “Nick”-label) or as session-menu (that would be the “Nick”-label). The order of the items in the list can be changed by DND.

• Something like a middle-click shortcut on the first item in the list. Possibly show the first item's icon next to the label, if session-menu look is chosen. — Simon Steinbeiß 2011/07/16 13:01
• Two options for the session-menu: “icon-only” and “label-and-icon” (use the icon of the first item in the menu). This is mostly thought of as a visual improvement. — Simon Steinbeiß 2011/07/16 13:01