Issue831chartsNotWorkingInDocker

• Replacing Python 2.x basestring with Python 3.x str. Charts working now, with the exception of the CT chart of study DLP over time: does it work for anyone else? The radiographic chart of kVp over time works, so this seems to be CT-specific. References issue #831

• Fixed the problem where radiographic charts of kVp etc over time failed if some data values were None. CT study DLP over time still has no data, and haven't addressed Ed's referenced-before-assignment problem yet. References issue #831

• @edmcdonagh does this fix the problem that you had with your DX chart? I am unable to replicate the error that you have seen. References issue #831

@Ed McDonagh I’d like to pull this back into develop before I create an issue 830 branch to revamp the chart Python and JavaScript code.