Bias

@rsignell-usgs Can you take a quick look at this?  I am planning to add this to the main notebook and generate the table at the end in a weekly basis.  What do you think?

Here is the rendered HTML view,

http://nbviewer.ipython.org/github/ocefpaf/secoora/blob/bias/notebooks/inundation/compute_bias.ipynb

PS: travis is running in my SECOORA branch:
https://travis-ci.org/ocefpaf/secoora

However, it would be nice to have it up and running at the main repository (ioos/secoora).  Do we have an ioos travis account?