Fix failing tests. The reasons for the failures were in the following categories:
- changes in the snapping algorithm that made the axes off by one pixel.
- changes in text alignment.
All the text in the baseline images is non-antialiased. This seems to be more robust to differences across freetype versions. This involved the addition of a new rcParam 'text.antialised', used only by the Agg backend.
Additionally, some freetype-related differences still cause failures. For those, we mark the tests as known fail if the user has a version of freethe versions that we expect to worvesions were determined using T. Robitaille's freetype differences testing tool here:
Fix single pixel markers. The pixel shape is now optimized so it does the right thing in the Agg backend. For raster backends, linejoin and cap styles is now correctly passed to and used in the backend.
Fix bug in polar plots: if rmax - rmin was too small, the old rpad padding heuristic broke down and sent the rlabels way off of the plot axes. The new approach is to not have rpad, but to change the alignment of the rlabels depending on the quadrant of the plot. This seems to work quite well, but is perhaps slightly backward incompatible.