------ - Better error handling - Updated min. versions for requirements
0.1.31
------ - Include ticker in error message if error is raised
0.1.30
------ - Fixed Yahoo!'s 30m bars being returned as 60m/15m
0.1.29
------ - Fixed issue with Pandas "DataFrame constructor not properly called!" - If ``threads`` is set to True, it will default to number of tickers (max = of CPU cores)