Implement typed_array

[jjerphan]

A layout class and the array_data structure are gathered into the typed_array template class, which provides an API very similar to that of std::vector:

template <class T, class L = get_default_layout_t<T>>
class typed_array
{
public:
    
    using layout_type = L;
    using reference = typename layout_type::reference;
    using const_reference = typename layout_type::const_reference;
    
    size_type size() const;
    reference operator[](size_type);
    const_reference operator[](size_type) const;
    
private:
    
    layout_type m_layout;
    array_data m_data;
};

Design from @JohanMabille.

[JohanMabille]

This API is non exhaustive, the typed_arrya should also have the iterators, front / back, etc ..