Github-to-sqlite

* New command: `github-to-sqlite issue-comments` for importing comments on issues - 7
* `github-to-sqlite issues` now accepts optional `--issue=1` argument
* Fixed bug inserting users into already-created table with wrong columns - 6

* Added `github-to-sqlite repos` command, 3

* `license` is now extracted from the `repos` table into a separate `licenses` table with a foreign key, 2

* Added the `github-to-sqlite starred` command for retrieving starred repos, 1

* Fix bug in authentication handling code