Network settings overhaul [Postponed for 2.6]

Backported from latest gnome-control-center
Then improved in various ways

1. Merged NetworkManager and the panel [Partially Done by backport]
2. Fix wireless networks list, its too clumsy [Finished, uses buttons now]
3. Improve icons and other UI elements such as placement of buttons [Finished]
4. In proxy, when none is selected, the fields for the proxy settings still show up [Fixed by backport]
5. Show IP address for wireless possibly others [Fixed by backport]

Needs testing, especially wired, broadband, and other network types