gdbus: Use gcc builtin instead of g_atomic

g_atomic_* end up using G_STATIC_ASSERT, causing gcc 4.8 to yell due to
-Wunused-local-typedefs.

gdbus/client.c: In function ‘g_dbus_client_ref’:
/usr/include/glib-2.0/glib/gmacros.h:162:53: error: typedef ‘_GStaticAssertCompileTimeAssertion_2’ locally defined but not used [-Werror=unused-local-typedefs]
 #define G_STATIC_ASSERT(expr) typedef char G_PASTE (_GStaticAssertCompileTimeAssertion_, __COUNTER__)[(expr) ? 1 : -1]
gdbus: Fix not calling property_changed callback

In case a property did not appear by the time proxy_added was called
property_changed has to be called if it appear latter otherwise the
application will be unaware of it.
hfp_hf_bluez5: Add audio card .connect() for HFP 1.6
hfp_hf_bluez5: Remove redundant parentheses
include: Add ofono_handsfree_audio_has_wideband()

As we can assume that the CVSD codec will be always available, the only
information that we need to export is if we have support for wideband
codecs.  Right now only mSBC is defined as wideband.
handsfree-audio: Implement ofono_handsfree_audio_has_wideband
handsfree-audio: Remove unused 'codecs' field from agent

Now that we only keep track whether we support wideband speech or not, we
don't have to keep track of the list of codecs supported by the Agent.
include: Remove hfp bits from types.h
core: Add hfp.h

This will serve as a collection point for all HFP related definitions.
drivers: Include hfp.h
hfp_hf_bluez5: Include hfp.h
core: Include hfp.h
handsfree-audio: Move codec enums to hfp.h
hfpmodem: Send AT+BAC with the supported codecs

Before, the AT+BAC command was being sent with fixed information,
now we send the command (that inform the AG of the codecs supported by
the HF) with the codecs supported by the registered Handsfree Audio
Agent.
hfpmodem: Add codec watcher register

This patch adds a function to monitor when the AG sends a new codec
before establishing the SCO connection.
hfp_hf_bluez5: Register codec watcher

This patch registers the codec watcher when the Handsfree Audio Card
driver probe callback gets called.
include: ofono_handsfree_card_select_codec()

This will be used by the drivers that a given codec was negotiated
for a card.
handsfree-audio: Implement ofono_handsfree_card_select_codec()
hfp_hf_bluez5: Set the audio codec in the card

This patch updates the handsfree audio card codec when the AG notifies
the codec for the succeeding incoming SCO connection.
handsfree-audio: Send the selected codec

This patch removes the hard-coded CVSD codec, and adds the selected
codec in the NewConnection method call, notifying the agent the codec
previously selected for the audio connection.