Spring layout

• Updated default --biogridversion version to 4.2.191

• All generated networks get networkx spring layout added by default

• Added tqdm progress bar support. Set --noprogressbar flag to disable

• Added --skipupload flag to skip the upload to NDEx step

• Added logic to retry failed upload of network to NDEx.
  --maxretries and --retry_sleep allow caller to control
  behavior

• Added --organismfile and --chemicalsfile to let caller override
  defaults