add a new animation framework for MapCube and other ndarrays
Update mapcube plotting with a new interactive mpl fig.

This adds a new interactive controls to the mapcube plotting
via the peek() method. plot() now does not come with controls
and returns only the matplotlib animation instance.
Make plot not use the new animation class.

peek() now returns a interactive explorer while plot() returns a
standard FuncAnimation instance.
Fix a bug in MapCube.plot and GenericMap.resample
remove print statement