Test audio timeline boundaries and sustained SoundTouch playback

src/call/voice_sources.cmake

@@ -20,6 +20,7 @@ function(utun_setup_voice LIB_DIR CALL_DIR)
         ${CALL_DIR}/call_audio.c
         ${CALL_DIR}/call_tones.c
         ${CALL_DIR}/call_jitter.cpp
+        ${CALL_DIR}/call_timeline.cpp
         ${_src_dir}/radio/radio_jitter.cpp
         ${_src_dir}/radio/radio_audio.c
         ${_src_dir}/stream/stream_playback_audio.cpp