Allow buidling from filesystem
Scraper cleanup

Enable scraping from files by specifying a ``--fromfiles``
option.  When reading from files, don't stream
the JSON, as the parsing was causing CPU usage to jump to 100%.

Paramaterize the location of cached files and the logfile.

Use ``path.join()`` to build paths instead of string
concatenation.

Remove use of Set from collections, thus eliminating need for
collections as a dependency.

Include data items that are in the state (cdc.txt) dataset, but
not in the GSC scrape, in the final output.
Eliminate unused variables, use static trick instead of global
Cleaner request throttling

Use ``async.queue`` instead of my janky implementation.  Use
module pattern to encapsulate variables related to scheduling.