GetItemList

Added Fancy Indexing for sparse matrix.

NEWS.txt
- Add a_sparse_matrix[vector of int] -> another_sparse_matrix (Jeremie Tanguay)
- Add a_sparse_matrix[vector of int, vector of int] -> dense vector (small difference from scipy, as it was returninng a one row numpy.matrix that we don't implement) (Jeremie Tanguay)