REL: v3.4.1

This is the first bugfix release of the 3.4.x series.

This release contains several critical bug-fixes:

* fix errorbar when specifying fillstyle
* fix Inkscape cleanup at exit on Windows for tests
* fix legends of colour-mapped scatter plots
* fix positioning of annotation fancy arrows
* fix size and color rendering for 3D scatter plots
* fix suptitle manual positioning when using constrained layout
* respect antialiasing settings in cairo backends as well