std_complex.h (std::complex<>::real): Return a reference.

        * include/std/std_complex.h (std::complex<>::real): Return a
        reference. Add non-const overload.
        (std::complex<>::real): Likewise.
        (std::real): Likewise.
        (std::imag): Likewise.
        (std::operator+): Tidy.
        (std::operator-): Likewise.
        (std::operator*): Likewise.
        (std::operator/): Likewise.
        (std::operator>>): Likewise.

From-SVN: r75680