modified to allow multiple active phasespaces recording data, and disables a phasespace if active and set as the source
added setters for world properties: material, size, colour
removed redundant SetupHead method
removed redundant 'update' methods, now performed from Python wrapper
specifying material for vacuum in the example geometry
removed confused properties and setters in Volume
fixed inheritance behaviour with repeats, cannot have nested inheritance yet
added documentation to methods, moved functions to the top of the file
removed unused  class and function