ENH: Plot missing observations
I'm trying to find a home for this function: https://gist.github.com/TomAugspurger/9156696

Output is shown [here](http://tomaugspurger.github.io/blog/2014/02/22/Visualizing%20Missing%20Data/).
Basically it highlights the locations of missing data.

Should it go
- Under `df.plot(kind='missing')`
- As a recipe in the cookbook
- Elsewhere (seaborn)

I've been talking with Michael from seaborn and he thinks it could be in scope for pandas since it's essentially a view on the DataFrame.

It's possible that I already posted about this, and we already made a decision, but I could remember and search didn't turn up anything.
