* src/NetworkManagerAP.c
		- (nm_ap_new, nm_ap_new_from_ap): Don't crash when we don't have
			enough RAM to allocate new AP structures, but return NULL instead

	* src/NetworkManagerAPList.[ch]
		- (nm_ap_list_is_empty): new function
		- (nm_ap_list_combine): new function, combine two access point lists
		- (nm_ap_list_copy_keys): new function, copy keys from one list
			into another

	* src/NetworkManagerDevice.[ch]
		- Rename some functions to be clearer:
			nm_device_get_best_ap_frozen -> nm_device_is_best_ap_frozen
			nm_device_just_activated     -> nm_device_is_just_activated
			nm_device_activating         -> nm_device_is_activating
			nm_device_now_scanning       -> nm_device_is_scanning
		- Cache the last 4 scans so that the access point list is more stable.
			We combine the lastest two scans and use that as the AP list,
			and diff that combined list against the combination of the earliest
			two cached scans for the WirelessNetworkAppeared/Dissappeared signals


git-svn-id: http://svn-archive.gnome.org/svn/NetworkManager/trunk@210 4912f4e0-d625-0410-9fb7-b9a5a253dbdc