Added a persistant "warning counter" independent of flair

I've wanted to keep track of "warned" users for a while and I added a quick hack to do that. Pickled the dict to a file so that it will persist across reboots of the bot. Displays how many times user has been warned so that the mods can easily spot repeat offenders; maybe implement an auto-ban for a certain number of warns.

I know we sort of use flair to track this kind of stuff but flair tracks warns *and* downvoted posts. I'm interested specifically in how many times a user was so dumb a mod had to issue a warning.

TODO: implement this (and possibly other user tracking) using an sqlite3 database instead of pickling like a dumbass.