Switch to scraping Google Code

The Google Code Issues API was shut down in June, so the current version no longer works at all. I rewrote a significant chunk of the script to instead scrape issues from the Google Code site.

Other changes along the way:
* Added links to the Google Code issue when the original has attachments. Not really ideal, but a bit better than nothing.
* Linked users names to their Google Code profiles.
* It now splits comments which are over Github's maximum size into multiple comments (which fixes #28).
* Fixed #26.

Probably some regressions in the bits I didn't need, since I ended up having to rewrite a bunch of stuff.