a minor fix of blocking_input.py
Modified EllipseCollection for closer compatibility with Ellipse patch.
Make plot_directive use a custom PlotWarning category.
minor refactoring of the ps backend
make backends registerable
fix axis_artist bug
support picking of axes objects outside their bounding box
draggable legend now optionally blitted
fix axes_grid for offsetbox api change
refactor draggable legend to support annotation
