Support friends (does not poll yet)

Also revamped some command-line options (--add-top)
Umm... More options. Lots of options.

Lots of command-line options.
* "Friends" functionality works.
* Ability to sync reddit friends with users in database
* Ability to scrape user pages, /r/friends, or both.
* Adding the /top users is now optional
* Exclude subreddits via commandline
* Add users via commandline
* Set configuration values via commandline

Also:
* Duplicate albums are ignored earlier (does not get_highest_res first)
* Does not log when a post/comment is already in DB