Add a class codec on client side to manipulate codec-related data.
Add a screen that displays on call the number called and the codec used.

note: the screen doesn't display when a call is made with the keypad. TODO

The combo box displays the default or the selected codec

The user can select a codec among the supported one's in the audio settings tab of the config window.
The call is made with only this codec.

TODO: use the other supported codecs to place a call, if the selected one doesn't work

We use now only one button to pick up and place a call

Document managerimplg.cpp.

Ébauche de l'implémentation du call D-Bus "setCodecPreferedOrder" dans managerimpl.cpp

3 codecs for sdp negociation

Sampling rate values are no more hardcoded. The sampling rate of the audio layer
 and the frame size can be set in the user config file. The clock rate of the codec we use
in the rtp session is set with his actual value, but can be changed by modifying
the available codec in the user config file (only G711 for now)

If an registered account is set by default, a call is placed with this account.
If no account is set by default, the call is made with the first registered account of the list
If a non-registered account is set as default, no call is placed and a message popup is thrown.

Conflicts:

	sflphone-gtk/src/calltree.c
	sflphone-gtk/src/menus.c
	sflphone-gtk/src/sliders.c