Add a query feature for public course datasets

[npaun]

Problem:

• You'd like to be able to look up COMP 362 without having to look at the course schedule, bwckgens, and all kinds of online stuff.
• SQL syntax might actually be less painful than McGill's query interface.
• You'd like a quick dump of all COMP courses offered this year (or next year too).
• Somebody posted a course averages dataset online, and you'd like to make use of it.

Solution

• Minervaclient could load bwckgens.csv into a SQLite database, and implement a few simple requests (by course, by department), and then let you use SQL to query the rest.
• We could integrate the course averages dataset, and figure out how to manually scrape through the calendar to find pre-reqs, etc.

[npaun]

This would fix #20 too.