[numpy] array spec is "type [][][]" (for dim 3) intead of "type array 3"
[numpy] data offset is a shared_ptr
[numpy] shape is a shared_ref
[numpy] add ndim attribute to numpy array
[numpy] add strides attribut
[numpy] add iterator for numpy
[numpy] add size attributes
[numpy] add itemsize attribute
[numpy] add flat iterator for numpy array
better use of std library
[numpy] assignation of subarray in an array
[numpy] add str to numpy array
[numpy] add tests for numpy