Merge "RFC sdp: Initial SDP creation"

include/asterisk/rtp_engine.h

include/asterisk/sdp.h

include/asterisk/sdp_options.h

include/asterisk/sdp_priv.h

include/asterisk/sdp_state.h

include/asterisk/sdp_translator.h

include/asterisk/stream.h

main/rtp_engine.c

main/sdp.c

main/sdp_options.c

main/sdp_private.h

main/sdp_repr.c

main/sdp_state.c

main/sdp_translator.c

main/stream.c

res/res_sdp_translator_pjmedia.c