traits.hpp:
* split traits into "view traits" and "mutable traits"
experimental:
* added new folder for emerging/unfinished features
experimental/sparse_view.hpp:
* added new class c_array_view which presents a T* array and a size as vector_view
* added new class compressed_matrix_view which wraps three arrays into a matrix_view
detail/concepts.hpp:
* prepared vector_view concept (still disabled because further work is needed here)
[SVN r56003]