adding auto ticks example

[choldgraf]

This is a quick example that demos the changes described here (based off of the question we just had at the BoF)

http://matplotlib.org/users/dflt_style_changes.html#plot-layout

The basics seem correct, but for some reason the plots aren't changing when I'm changing the rcParams. Any idea why that might be?

[tacaswell]

this is actually changing the rcparam, this should be

with plt.rc({'axes.autolimit_mode': 'round_numbers'}):
   ...

and similar below.

[choldgraf]

updated this so that it displays different patterns of behavior now. the example plots don't change a ton but that's probably OK as the main goal is just to expose this API so people know it's a thing they can tweak if necessary.