Data pipeline rewrite - Githubissues

The data pipeline has been rewritten to play well with the SIS API.

All data is now explicitly fetched and stored efficiently. The explicit advantages are:

No 404's on API querying, and querying done in parallel using all processor cores.
Querying time down to 7 minutes per day!
Total amount of class data for frontend use down to 12 MB.
Cross-listed courses information now available.
Final exam information more explicitly stored.
ALL classes in the semester explicitly recovered from API.

Fixes #82, #77, #67 and #35

mDibyo / berkeley-scheduler