@sven-herrmann pointed out that m_normalW is not initialised.
@sven-herrmann pointed out that m_normalW is not initialised.

It's not fatal as all design commands set it but just in case
somebody wants to use that class in isolation. Thanks for the fix.

berndporr/iir1,berndporr/iir1,berndporr/iir1,berndporr/iir1