This is the third bugfix release of the 3.5.x series.

This release contains several bug-fixes and adjustments:

* Fix alignment of over/under symbols
* Fix bugs in colorbars:
    * alpha of extensions
    * `drawedges=True` with extensions
    * handling of `panchor=False`
* Fix builds on Cygwin and IBM i
* Fix contour labels in `SubFigure`s
* Fix cursor output:
    * for `imshow` with all negative values
    * when using `BoundaryNorm`
* Fix interactivity in IPython/Jupyter
* Fix NaN handling in `errorbar`
* Fix NumPy conversion from AstroPy unit arrays
* Fix positional *markerfmt* passed to `stem`
* Fix unpickling:
    * crash loading in a separate process
    * incorrect DPI when HiDPI screens