In base.py history(), session.get can return None or 404. Clarify exception catching within the history() method of base.py.
Ensure none and 404 values are caught prior to quote processing.
This prevents json parse exception, connection exception, or unbound exception from being thrown during data collection.
Includes updated unit testing.
Before this commit there was no option to get the last 4 years' Shares Outstanding of a company. Now, this numbers can be found at the <code>Ticker.shares</code> attribute. Specifically, they refer to the average number of basic shares for each year.
Flávio Veloso Soares