Initial integration of the new MM iface in NM

[Aleksander Morgado <aleksander lanedo com>]

This series of patches add the basic integration needed in NetworkManager in
order to handle the new 'ModemManager1' interface.

The first 9 patches basically prepare the codebase to easier integrate the new
interface. Some additional cleanup is done in several places.

[PATCH 01/15] modem-manager: split the `NMModem' object
[PATCH 02/15] modem-manager: remove the `device' property from
[PATCH 03/15] modem-manager: switch the `state' property from
[PATCH 04/15] modem-manager: let the `NMDeviceModem' handle
[PATCH 05/15] modem-manager: rework interface related properties in
[PATCH 06/15] modem-manager,gsm: keep the "Connect" DBus call
[PATCH 07/15] modem-manager,gsm,cdma: remove 'signal_quality'
[PATCH 08/15] modem-manager: fix several code alignment issues
[PATCH 09/15] manager: trivial fix in object type in signal callback

The remaining 6 patches introduce the new ModemManager support, implemented by
using the new `libmm-glib' library provided by ModemManager itself.

[PATCH 10/15] build: new `--with-modem-manager-1' to check for new
[PATCH 11/15] modem-manager: new `NMModemBroadband'
[PATCH 12/15] manager: create a new GDBus-based `MMManager' if
[PATCH 13/15] device-bt,device-modem: listen for data port changes
[PATCH 14/15] modem-manager: don't report the data interface along
[PATCH 15/15] device-bt: watch both old and new ModemManager

But beware!

The UI applications making use of ModemManager directly are not yet updated. For the specific case of the gnome-control-center, it will let you enable/disable modems directly from the "Mobile Broadband" switch only if the modem is already unlocked or if it doesn't need a PIN. If you add the PIN number in the NM settings, it will let you activate the connection directly, though.

If your modem is locked, you can always run:
   $> sudo mmcli -i 0 --pin=1234
(assuming 0 is the index of the SIM card in the Modem object.

`mmcli' now has a manpage, so you can also see further examples there.

Comments very welcome!

Cheers.