psyplot plot methods

This plugin defines the following new plot methods for the psyplot.project.ProjectPlotter class. They can, for example, be accessed through

mapplot(*args, **kwargs)	Plot a 2D scalar field on a map
mapvector(*args, **kwargs)	Plot a 2D vector field on a map
mapcombined(*args, **kwargs)	Plot a 2D scalar field with an overlying vector field on a map