Moved jubatus::sfv_diff_t to jubatus::core::anomaly::sfv_diff_t.
Moved jubatus::sfv_diff_t to jubatus::core::recommender::sfv_diff_t.
Merge pull request #346 from gwtnb/namespace-anomaly-recommender-type

Fixed namespace sfv_diff_t in recommender_type and anomaly_type (#343)