added switch_backend bugfix from sf patch 1979402
added dtype patch from sf 1980695 for mlab.load
Fix crash in Agg drawing collections with no fill and/or edge color.
Fix STIX fonts table (just use a raw image).
Fix STIX fonts.
Fix some mis-typed URLs
fixed a bug for log-scale stacked histograms
updates to site docs
Added support for log to hist with histtype='step'
continue conversion of docstrings to restructured text
