Both the ModemManager daemon and the mmcli will now include `libmm-glib.h' only.
We also handle two new special `_LIBMM_INSIDE_MM' and `LIBMM_INSIDE_MMCLI'
symbols, which if included before the `libmm-glib.h' library allow us to:
* Don't include the libmm-glib high level API in the ModemManager daemon, as
the object names would clash with those in the core.
* Define some of the methods of helper objects to be included only if compiling
ModemManager daemon or the mmcli.
Avoid trying to merge all interfaces into the same set of APIs, and keep having
a specific object (proxy) for each interface handled by the GDBusObjects
reported listed by the GDBusObjectManager.
