Add missing specialization of evaluator of sub-sparse-matrices that can be seen as a SparseCompressedBase. This changeset enable faster iterator for such expressions.
Add missing specialization of evaluator of sub-sparse-matrices that can be seen as a SparseCompressedBase. This changeset enable faster iterator for such expressions.

madlib/eigen_backup,rotorliu/eigen,madlib/eigen_backup,rotorliu/eigen,madlib/eigen_backup,madlib/eigen_backup,rotorliu/eigen,rotorliu/eigen