Allow NaN as metric result value and make some small cosmetic code changes for clarity

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1416651 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1124 Deprecate ununsed recommenders

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1418226 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1127 - Fixed iris test to be better test (and be deterministic, too)

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1422165 13f79535-47bb-0310-9956-ffa450edef68
MAHOUT-1127 - Slight addition to previous fix

git-svn-id: https://svn.apache.org/repos/asf/mahout/trunk@1422175 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'trunk' of https://github.com/apache/mahout into skm
Added DecoratedVector<T> and refactored vector classes.
Updated .gitignore.