Count fever occurence by zip code

To run:

python3 fc.py -readings <readings data file> -user_data <user data file> -output <output file>

All parameters are optional and default to readings.jsonl, user_data.csv, and results.txt

Result is a tab delimited file with a header. For example:

---
zip,total
12198,3
13464,2
30585,6
...
---

Assumptions:
- Users have a unique zip code
- ID has a fever if and only if there is at least once temp > 99.5
- Multiple fever results count at 1

Improvements (tbd):
- Catch errors in all input
- Catch mismatch in readings vs. user data (e.g. a reading without user data)