Integrate dbus-c++ and iax2 libraries in the main build system

libs/dbus-c++/examples/hal/Makefile.am

libs/dbus-c++/examples/hal/hal-listen.cpp

libs/dbus-c++/examples/hal/hal-listen.h

libs/dbus-c++/examples/properties/Makefile.am

libs/dbus-c++/examples/properties/propsgs-client.cpp

libs/dbus-c++/examples/properties/propsgs-client.h

libs/dbus-c++/examples/properties/propsgs-introspect.xml

libs/dbus-c++/examples/properties/propsgs-server.cpp

libs/dbus-c++/examples/properties/propsgs-server.h

libs/dbus-c++/include/dbus-c++/api.h

libs/dbus-c++/include/dbus-c++/connection.h

libs/dbus-c++/include/dbus-c++/dbus.h

libs/dbus-c++/include/dbus-c++/debug.h

libs/dbus-c++/include/dbus-c++/dispatcher.h

libs/dbus-c++/include/dbus-c++/error.h

libs/dbus-c++/include/dbus-c++/eventloop-integration.h

libs/dbus-c++/include/dbus-c++/eventloop.h

libs/dbus-c++/include/dbus-c++/glib-integration.h

libs/dbus-c++/include/dbus-c++/interface.h

libs/dbus-c++/include/dbus-c++/introspection.h