Major change to compression infrastructure

This pull request is a major revamp of the compression. Before logging, an empty folder has to be created. It is then supplied as the bag_folder argument to strandsbag record. Videos and rosbag are then stored inside this folder. The logging service is supposed to be used for when the patroller is at a waypoint. You call it with action:start folder:(WAYPOINT_NAME) to start logging at a new waypoint. To stop the waypoint recording, call action:stop folder:''. The idea is that we get the waypoints as single video clips and everything else as 6 second videos recorded continuously. This is handy for example for the people doing qsr. To play the bag, you first need to decompress the video using "rosrun libav_compressor video_decompressor.py _folder:=(BAG_FOLDER)". You then run strandsbag play with the bag_folder argument.

Left to do:
* Keep the camera info topic in the rosbag (currently filtered out by the regular expression).
* Get the correct camera frames from the topics.