Update defaults on everything

[jthorton]

We need to evaluate the default arguments on the API to be consistent with a certain type of input i.e. MLE or not see #172 for more details.

[jthorton]

We should move to using subplots in _master/pair_plot in future to make it easier for users to edit outside of the plotting functions.

Users would also like a presentation mode to improve the output, is there a way we can offer this or just improve all defaults to be suitable for a talk slide while still looking good in a notebook, see the seaborn defaults for each type here.