Ap 1624/backwards compatibility

[ccleung]

Tracker Ticket: https://quandl.atlassian.net/browse/AP-1624

Description:

• backwards compatiblity quandl.get method, as described by the master README (https://github.com/quandl/quandl-python/blob/master/README.md)
• analyst quandl.bulkdownload method:
  • example: quandl.bulkdownload('EOD', api_key='xxxxx', filename='/tmp/FOO.zip', download_type='partial')
  • download_type= is optional and will default to complete if not specified
  • filename= is optional, if not specified will download to the current working directory
  • api_key= is optional, api_keycan alternatively be set with quandl.ApiConfig.api_key='xxxxx'

    Note to the reviewer:

    Is there a migration?

(Running time? Downtime?)

Dependency(if any):

• updated class definitions from: https://github.com/quandl/quandl-python/pull/41, https://github.com/quandl/quandl-python/pull/44

[mbasset]

@ccleung looks good. A few suggestion.

[mbasset]

:+1: