Code cleanup

[edfan]

Yikes.

• [ ] clean up script.js
  • [ ] stop using globals
  • [ ] refactor the unreadable array / object accesses
  • [ ] refactor into separate files
  • [ ] add more comments
• [ ] merge and document old_scripts / new_scripts
  • [ ] provide instructions for running the eval scraper, the csb-based scraper, and the coursews-based scraper
• [ ] clean up img