Houdini I/O pipeline

There are no completely new features in the Houdini 19.5 update this time. Rather, there are fundamental revisions to the most important functionalities of Houdini: RBD Rigid Body Dynamics and Fluids Simulations. I/O, i.e. input & output, is another topic that extends across all tools. And as expected, there are some user interface standardisations and improvements - especially in the interactive tools. Let's dive right in!