Add details for new filters in README and example YAML
Blacklist and FirefoxHistory output filters

The BlacklistFilter allows checks the value of a key against blacklisted values.
 - Multiple blacklists can be specified in the config file
 - Multiple keys can be matched against a single blacklist
 - Keys to match can be of the form 'a.b' to match "b" in {"a": {"b":"foo"}}
 - Matching can use python regex or straight string compare
 - The values to match are stored in flat files that use # to indicate a line of comments

 The FirefoxHistory filter basically does what ChromeHistoryFilter does but for firefox.
Install precommit hooks and do lots of guided cleanup

Running filters now works in a nice virtualenv.
If you don't know how to use virtualenv, read up:
  http://codefellows.github.io/sea-f2-python-sept14/supplements/virtualenv.html