FIX: Make legends show up in ipyton notebook
FIX: Make legends show up in ipyton notebook

This adds a workaround for a bug in the tight layout code in
matplotlib. The next version of matplotlib has the same fix
internaly, so this workaround is not needed for  matplotlib >1.3.1
https://github.com/matplotlib/matplotlib/issues/2530

Closes: yhat/ggplot#33

has2k1/plotnine,has2k1/plotnine