Scatter Plot Feature

[teubert]

Add new feature to produce a scatter plot of states. Also, added to basic example and tutorial.

Can be called directly from the result of the state estimator (UKF or PF). Like so:

states.plot_scatter() # Simple scatter chart

Also allows you to overlay multiple states on one chart:

fig = initial_states.plot_scatter() # Simple scatter chart
future_states.plot_scatter(fig=fig) # Add future states to same chart

Everything that's configurable from the scatter function in matplotlib is configurable using kwargs, e.g.,

fig = initial_states.plot_scatter(c='b') # Blue points

Also, you can specify a subset of the keys to plot. E.g.,

fig = initial_states.plot_scatter(keys=['state1', 'state2']) # Only plot state 1 and state 2

Here's what it looks like: