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