improved reputation

new features:
- refactoring for modularity and maybe a fully-featured sexpr parser one day
- (rep top) and (rep bot) commands to list top/bot scorers
- changed data store to a redis sorted set key called "reputation" (http://redis.io/topics/data-types for more)***
- support for 1+, 1-, and 1?
- more robust whitespace handling
- run.sh to set redis env vars

***this means we have to start the karma counts over again as there is no migration code