YTAnalytics 0.1.0

• Allows a vector of video ids or playlist ids to be passed to video and playlist functions.
• Fixed an issue with dates where dates not passed as characters threw errors. Date objects and strings are both acceptable now.
• Fixed issues with most playlist functions that had ;isCurated==1 missing from its filters.
• Removed playlist_cities as playlist city information is not made available through the API.
• Fixed typo with playback_location file name
• Changed error_checking message to warning