Clean up dynamic_cast's in pipeline directory

We often use dynamic_cast when we really want to check if something is an exact type. dynamic_cast is unnecessarily expensive for this use, and we should use typeid instead.

For example, we could create a helper as follows:

template <TargetClass>

bool exactDynamicCast(void* srcObj) {

    return typeid(TargetClass) == typeid(*srcObj);

}