Call someone, add incoming calls to the conference using the new conference button

Signed-off-by: Alexandre Savard <alexandre.savard@savoirfairelinux.net>

Which send a signal through DBUS

test for multiple conference participants

MainBuffer::getData
MainBuffer::putData
MainBuffer::discard
MainBuffer::flush

Now, creation and deletion of rngbuffers is automated.

It fixes the problem concerning discarding the data

create, remove, get, store  ReadPointer

Data captured during call dialing is now flushed when rtp thread is started
(like pulse audio)

However, Audio stream for both Alsa and PulseAudio should be stopped
see

Currently we are pooling the playback and the capture devices
in the same function

Idealy we should use the Alsa interuption mechanism by implementing
playback_callback and capture_playback SEPARATELY

There is still a problem with the capture as it start to fill the
ring buffer at the same time than the playback (i.e. as soon as the tone occurs)
which introduces latency during the call.

However, Microphone Capture using alsa cannot be copied inot ring buffer.
The application was by passing the micRingBuffer in this case...

Conflicts:
	sflphone-common/src/sipvoiplink.cpp
	sflphone-common/src/sipvoiplink.h

This buffer is not one coresponding to the call ID since we do not
want to send back the incoming data
In case of a conference, we just need to extend this id to a set of ids
and mix them together if the set is greater than one

Only the pointer from the ringbuffer map were erased,
not the ring buffer itself...

The audio frame is copied into the right ring buffer given the CallID
as an argument

Put(int), Get(int), Put(float), Get(float),
using two pointer (which should be in AudioLayer and in AudioRtp)

Since the AudioRTP pointer is now in SIPcall, we need to pass the
call object as a parameter.

Conflicts:
	sflphone-client-gnome/src/config/configwindow.c
	sflphone-client-gnome/src/menus.c

[redmine_down] crash when hanging up a dialing call because tries to add it to history whereas no starttime