Using pathlib

The ScrapeRepo.py script now uses pathlib. There have also been many changes/rewrites to the script eliminating a few bugs:

• Using pathlib has made it easier to build new paths and to read the code.
• The dictionaries holding filenames all use Pathlib objects instead of strings.
• Building a list of VTK modules from the source files is now threaded.
• Building tarballs is also threaded.
• Building the caches is now all threaded.

Performance:

Version	Build Caches	Caches built
Previous	233s	2.3s
Current	64s	2.7s