Added ability to discourage brute force login attacks by penalizing failures.
Shifted the penalties by one level.
Document options relating to login attempt limits
Fixed typo in lastLoginField option.
Merge branch 'master' of https://github.com/smcmurray/passport-local-mongoose
Forgot to wrap options.limitAttempts around a couple actions, and also forgot to save to db.
Added test for limitAttempts
Added test for setting 'attempts' field name.
Correct model for attemptsField override test
Merge pull request #53 from smcmurray/master

Added ability to discourage brute force login attacks