Add example for discrete_scatter

[SvoONs]

Fix #166 by adding an example file using the titanic dataset and also extending the dosctring of discrete_scatter with said example.

[SvoONs]

Apparently, I broke the build... I will have a look. Also I noticed the arguments unique_c and clip_outliers are not documented yet, I will come up with proposals.

[amueller]

Thanks, fixing the docs would be very welcome as well!
Hm the same failure is in #180 I must have messed this up myself.

[amueller]

Seems like a regression in pandas 1.0 that broke CI: pandas-dev/pandas#31469

[amueller]

can you please do another commit to trigger CI again? I just moved the repo to its own org which reset all the CI.

[amueller]

hm the failure is related to your change though I'm not entirely sure what's going on. Looks like a bug in the discrete_scatter code maybe?

[amueller]

Couldn't reproduce the error locally. Sex might also not be a good example for a scatterplot given that it's categorical. It might work after #175 but right now it'd look pretty boring.

[SvoONs]

I can reproduce the error locally using pandas==1.0.0. If I downpin pandas tests pass.
I picked a different dataset for the example, let me know what you think.

[amueller]

If you merge master, the error will go away. I pushed a work-around. And yes, that example looks great, thanks!

[SvoONs]

I had to create the figure using plt.figure() in the docstring example in order to make doctest pass. In my local setup it also works without, a bit weird.

[amueller]

That's a bit odd but looks good now! Thanks!