Ensure than an input port is only mapped once
Ensure than an input port is only mapped once

Kitware/sprokit,linus-sherrill/sprokit,linus-sherrill/sprokit,mathstuf/sprokit,mathstuf/sprokit,linus-sherrill/sprokit,Kitware/sprokit,mathstuf/sprokit,Kitware/sprokit,linus-sherrill/sprokit,Kitware/sprokit,mathstuf/sprokit