Make viewlims demo more interesting by using events to regenerate a fractal.
Update AxesImage for independent autoscaling of x and y axes.
Remove trailing whitespace.
Add a demo for getting notified of an Axes' change in view limits.
Small fixes to test_pdf_use14corefonts.py, thanks to Nicolas Grilly
Commit Nicolas Grilly's use14corefonts patch
Minor comment and indentation fixes.
axes.py: add comment describing separation of XY plots and polar plots
axes.py: eliminate redundant attribute lookup
doc bug: update axvline docstring
