Initial PairGrid implementation
Preliminary hue grouping in PairGrid
Only make diag axes if needed
Some PairGrid tests
Add palette flexibility and tests
Factor grid figure palette creation into base class
Some more housekeeping to get legends working
Add PairGrid and pairplot to axisgrid docs
Add basic pairplot function
Be safe about default palette in tests
Don't add legend by default with FacetGrid.map
Update release notes
Skip font test on older matplotlibs for now

I am not sure why it is failing on Travis but as that is very hard to debug I will choose to disable it for the time being
Add more PairGrid and pairplot tests
Skip PairGrid tests with special diagonal on older matplotlibs
Merge pull request #262 from mwaskom/pair_grid

PairGrid and pairplot for drawing scatterplot (and more!) matrices