Visualizer & Logger

There is a utility header file common/logger.hpp, which is a logger for recording process starting and ending time, with respect to the component initialization time. Currently, only audio_pipeline and hologramuse this logger. Please create a log directory in your running binary directory to let those log files correctly appear.

log/visualizer.pyis a script to create visual timeline according to the log files in the same directory. It is not convenient to use or precisely correct right now.