Improved polyglot to do recursive checks, and detect numpy

[coldwaterq]

trafficstars

• Updated check_pickle
  • general results are unchanged, however now min_length can be used to avoid detecting tar files that often start with . as pickles.
• added checks for numpy and numpy pickles into find_file_properties
• added find_file_properties_recursively which checks the contents of tar and zip files

All of this should allow for the detection of more pickles in non-standard formats

[CLAassistant]

All committers have signed the CLA.

[coldwaterq]

Updated so that it should pass the lints and tests now. Can you re-run those checks?

[suhacker1]

LGTM!