Add missing epsilon/dummy_precision function in NumTraits<Array>
Add missing epsilon/dummy_precision function in NumTraits<Array>

madlib/eigen_backup,mjbshaw/Eigen,rotorliu/eigen,mjbshaw/Eigen,rotorliu/eigen,madlib/eigen_backup,rotorliu/eigen,rotorliu/eigen,madlib/eigen_backup,mjbshaw/Eigen,madlib/eigen_backup,mjbshaw/Eigen