Fixed race condition where blacklist counters could have had -1 time to live
Fixed some documentation inconsistencies
Added a method to allow a server to obtain the current count of blacklisted apps for statistical logging purposes
Made changes based on feedback from pull request

* Removed console.log statements
* Fix for not returning an error from redis_client.incrementExpiringKey method
* Fixed formatting of if clause
Merge pull request #11 from Kinvey/fixBlacklistCounter

Fix blacklist counter and add stats logging