use logging library to replace error_q and print
[rplidar_monitor] add thread.name, cleaning up
Merge branch 'dev'

* dev:
  Major re-write: 1. raw_points (Queue) and raw_frames (list of raw_frame) for future analysis; 2. current_frame (class of deque) for maintaining a fresh copy of the current frame for real-time plotting; 3. major reformatting and renaming to follow Google style guide
(1) added KeyboardInterrupt to terminate the program when CTRL-c is pressed; (2) raw_frames is Queue now, (for future file dumping implementation); (3) added some comments in rplidar_monitor
more comments in rplidar_monitor
add maxlen as a parameter of RPLidarFrame