Added ppp connection.

Ported from netcfg.
Added ppp mobile by porting from netcfg.
Revert "0.8 release updates"

This reverts commit 11a2b4d455d5d996b78a3fa5f72b6728b470338f.
Revert "Support more interface types"

This reverts commit 9ff72561e32ec6aa409f0c50757481a9032595ac.
Merge branch 'ppp'