Add Plotting Capabilities to Storm Object

[mandli]

Add a plot function to the Storm object that can

1. plot the track and time points of the storm,
2. plot a swath of the storm that is a given radius from the track,
3. and plot the category of the storm.

All of these have some options about how it determines what and how to plot. There are also some examples that have now been added to surge examples, especially as a means for looking at boundary conditions.