Prompted by this: http://stackoverflow.com/questions/18369798/how-to-get-ticks-on-both-sides-at-same-tick-locations/18371449#18371449
The demo looks like it relies on some auto-range magic to work correctly. Made more fool-proof.
Not sure if this should go against 1.3.x or master, targeted 1.3.x because (I think) it is easier to move the other way.
Also include pep8 clean-up
made example clearer
- use OO interface to set tick labels rather than pyplot
- explicitly set ax2.ylim, rather than relying on auto-scale magic
LGT% 👍 for merge