Added additional Attributes to simple.Podcast
Added get_podcasts_of_a_tag & get_toptags to public.py

API Endpoints "Retrieving Podcasts of a Tag" & "Retrieving Top Tags"
can now be accessed via mygpoclient
Also Toplist will now return a simple.Podcast including new attributes

TODO: update Unit Tests
Updated Tests to Changes to Podcast Objects
Added Support for Episode Data & Podcast Data Requests
Added Support for Listing Favorite Episodes
Added Functions & Tests for Settings URLs
Implement Functions for Settings
Format Code & add myself to AUTHORS File
Updated Tests for api.py
Missing Key in TagDictionary didn't raise Exception
Missing Key in EpisodeDictionary didn't raise Exception
Updated Tests for public.py