Tag Dispatching Protocol

The mechanism used to select algorithm implementations based on sequence family has been changed to use metafunction classes:

If your code implemented a custom sequence, it needs to be adjusted according to the above table; for example:

template<> struct begin_traits
{
    template< typename S > struct algorithm
    {
        typedef ... type;
    };
};

template<> struct begin_impl
{
    template< typename S > struct apply
    {
        typedef ... type;
    };
};