Minor tweaks to log messages, add new utility methods for future changes

git-svn-id: http://myrrix-recommender.googlecode.com/svn/trunk@523 0d189622-dca1-7e23-9e30-e8815eb7bd2f
Remove unneeded log message

git-svn-id: http://myrrix-recommender.googlecode.com/svn/trunk@524 0d189622-dca1-7e23-9e30-e8815eb7bd2f
Make it easier to swap in an alternate matrix inverter

git-svn-id: http://myrrix-recommender.googlecode.com/svn/trunk@525 0d189622-dca1-7e23-9e30-e8815eb7bd2f