Added in some error checking and also improved the ability to do compression via Ghostscript or PyPDF. The latter is needed to make sure things work consistently however that has environmental build issues or requirements whereas the latter is fully Python based as long as you have the pip libraries.
Added error checking + option to use PyPdf only so no GS dependencies (but doesn't work well all the time, so we still have to support GS). Then some command line help options.
