implement csv-logger from generic sioclient

[granawkins]

Fork of the default sioclient.py file which logs all readings to a .csv file in the base directory.

Expected behavior is:

1. Launch with python3 -m simoc_sam.csv_logger
2. Setup the socketio connection and begin receiving step-batch emits
3. Initialize a logfile as simoc_log_11-22-22_12-07-56.csv
4. For each batch, compile the list of fieldnames. Includes the timestamp and, for each field of each sensor, <sensor_id>_<field> (e.g. '6LC832_co2'). These correspond to 'columns' in the .csv.
5. If the logfile doesn't include all the fieldnames (i.e. sensors were refreshed), add new columns.
6. Write the batch to the .csv

Notes:

• Currently this needs to be launched independent of the server (just like the sensor_manager).
• Currently the file name is hardcoded with a timestamp, so it won't be continuous if disconnected/reconnected.
• The columns are mapped to sensor_id, as found in the SENSOR_INFO dict sent/maintained by the server. That means for sensors with a persistent id (Vernier, or Adafruit after we map them to USB ports), data will go to the same columns before/after refreshing or disconnecting the sensors. For sensors with random id (MockSensor, Adafruit currently), they will create a new column after each refresh.

[granawkins]

Could do. I was thinking it's useful to keep the vanilla sioclient.py as a template for future add-ons, but maybe that's not necessary.