uBLAS have missing accessors in some expressions

[correaa@…]

For example, these lines are missing from the class matrix_binary_scalar1:

    public: // around line 2925 in `matrix_expression.hpp`
        // Expression accessors
        BOOST_UBLAS_INLINE
        const expression1_closure_type &expression1 () const {
            return e1_;
        }
        BOOST_UBLAS_INLINE
        const expression2_closure_type &expression2 () const {
            return e2_;
        }

Without these lines is impossible to access to the expression template built by "d*matrix<...>". where d is a scalar. Other similar classes also miss this, in my opinion all this feature should be in based class.

This is most likely an oversight