include\eigenpy/numpy-type.hpp(32): error C2196: case value 'NPY_LONGLONG' already used

Co-authored-by: Joris Vaillant <joris.vaillant@gmail.com>

+ empty get_slice should return the slice type StdVec
+ set_slice with from >= to should throw
+ set_slice with incompatible iterator and slice sizes should throw

+ use ::allocator_type typedef by default, set as void for std::array

+ shortcut function exposeStdArrayEigenSpecificType now uses Eigen::aligned_allocator<T> for the slice vector

+ sets allocator for the std::vector<T, Allocator> returned by get_slice

+ add eigenpy::array_indexing_suite
+ add eigenpy::StdArrayPythonVisitor
+ add function template exposeStdArrayEigenSpecificType<MatrixType, std::size_t Size>