try to make it more readable/understandable

Remove some stuff we don't need:
    third_party libs
    Visual Studio / Xcode files
    symbian files

    pjmedia-audiodev (and update some source files accordingly)
    pjmedia-codec

    tests, documentation

define PJMEDIA_RESAMPLE_IMP PJMEDIA_RESAMPLE_NONE
    => so we don't rely on resample library

define PJMEDIA_HAS_SRTP     0
    => so we don't rely on srtp library

We do resampling and srtp ourselves anyway

remove unused functions

Move ALSA specific options to alsalayer only

we're using one unique mainbuffer instance inside managerimpl
remove use of setErrorMessage(-1)
simplify audiodriver creation

Now it's created before accounts

Instead it is part of Manager which is already itself a singleton
When the client requests termination of the daemon, the DBusManager instance
is not destructed, so we avoid using already freed memory

make Manager::(un)serialize static functions, they don't depend on the instance state
No need to check for the NULLity of _dbus anymore

Remove a useless argument to initConfigFile

sflphone-common -> daemon
sflphone-client-gnome -> gnome
sflphone-client-kde -> kde
sflphone-plugins -> plugins