Bugfix for Issue #31

Issue #31 found that TST evaluate was (almost) always classifying samples
as the first class.  After looking into it, it was apparent that there was an
error in the c++ crossValidate method.  Appears to work now.
Merge branch 'master' of github.com:JohnCEarls/AUREA
Merge branch 'master' of github.com:JohnCEarls/AUREA