Feature ap 243/v3 client

[ccleung]

Tracker Ticket:

• https://quandl.atlassian.net/browse/AP-352
• https://quandl.atlassian.net/browse/AP-1624 from: https://github.com/quandl/quandl-python/pull/42

  Description:

Updated python package, uses v3 api

Note to the reviewer:

for commit https://github.com/quandl/quandl-python/commit/d2034eb80a6cbb412e2047d7ec682adef4bfa2db:

• pass download_type as a query param to bulk download methods
• support both folder path and filename for bulk download
• updated tests and readme

  Note to QA:

• Ensure we test pandas/numpy data is expected
• Ensure data is returned in ascending order by default, and descending order if order type is specified
• Ensure README is clear and steps all work as expected
• Ensure api key and api version configurations work as expectged

[ccleung]

Everything is good to go, waiting for email to be sent out to python users, as well as final round of testing for this branch.

For reference, to install: pip install https://github.com/quandl/quandl-python/archive/feature-AP-243/v3-client.zip

[ccleung]

We need to add request_source and request_version: https://github.com/quandl/quandl-python/blob/master/Quandl/Quandl.py#L232