export/import config use associated vs. connected displays

[jugglefish]

Until a recent update of the nvidia driver disper was working quite nice on exporting/importing the config to easily switch different display configurautions (Laptop). Due to a bug with suspend/resume in 302.17 I now use 304.22 of the nvidia driver.

A simple 'disper -p | disper -i' will now fail unfortunatly.

The problem sits in the usage of the '[get|set]_screen_associated_displays' methods. The associated displays seem to report all "possible" displays that possibly could be connected. Now this is something completly different than the really connected displays. To me it seems that disper should rather use the connected than the associated displays when exporting the config.

Changing the behaviours of '[get|set]_screen_associated_displays' to use connected displays I could make disper work again like before the driver update.

The problem should probably rather be fixed by adding/using proper get/set_screen_connected_display methods in switcher/swnvidia.py.