As we continue to develop, tools are being made that sometimes create erroneous vg files which can lead to hard-to-figure-out errors in the other tools that read them. It would help both users and developers to have "vg validate" that can be used to verify if an input file is valid. The most common types of errors I'm seeing are within paths, where for example contiguous path segments are not connected by any edge. Same thing can happen in gams...