Fields Finished

Work on field selection is completed. This is by no means perfect nor
"production" ready. The parsing method for JSON is nasty. The issue is due to
how Asterix produces JSON response and how JSON from Python parses it.

I had to use string replace to add double quotes on a few items. This might
change as Asterix fixes bugs. For now it works.

Signed-off-by: Adam Brenner <aebrenne@uci.edu>