Add NetworkManager.h, which includes all of the other NM header, and
require all external users of libnm to use that rather than the
individual headers.
(An exception is made for nm-dbus-interface.h,
nm-vpn-dbus-interface.h, and nm-version.h, which can be included
separately.)
Remove _nm_object_ensure_inited(), etc; objects that implement
GInitable are now mandatory-to-init().
Remove constructor() implementations that sometimes return NULL; do
all the relevant checking in init() instead.
Make nm_client_new() and nm_remote_settings_new() take a GCancellable
and a GError**.
Since the API has not changed at this point, this is mostly just a
matter of updating Makefiles, and changing references to the library
name in comments.
NetworkManager cannot link to libnm due to the duplicated type/symbol
names. So it links to libnm-core.la directly, which means that
NetworkManager gets a separate copy of that code from libnm.so.
Everything else links to libnm.
