mapcube functions to get the data out as a 3d numpy array, and to get a list of the headers out.  Useful when working with mapcubes
added an empty line at the end
made the mapcube iterable.  len(mapcube) now returns the number of maps in a mapcube.
changes to the names of the convenience functions
updated docstrings
updated docstrings
adding placeholder for mapcube test functionality
made sure that the as_array function returns a copy, and not just a view in to the data
added .copy() to the as_array() function to ensure a new copy of the data is returned, and not just a view
removed the __iter__ so that there is only one way to access the maps; that way is mapcube.maps. This makes more sense.
tests for the new mapcube methods
added back distribute_setup.py - whoops
added in some documentation
added in double colon as per code review
added in tests as per review
changed the indexing of the mapcube in the docs
fixed mapcube reference
small edit to the docs
The ordering of maps in a mapcube is now more explicit
Explicit statement of the type of error raised when mapcube.as_array() is raised