added facility for running unit tests for the PDFgui dependencies.
Added convenience function loadStructure.
file should have been added
use new-style classes for all objects
Handle upper case X, Y, Z in the listing of space group operations.
this is necessary for Windows distributions.
Define the XLIB_SKIP_ARGB_VISUALS environment variable when starting
up atomeye.  This turns off transparency in Ubuntu 12.04 and hopefully
also on MAC.
added "composition" property for recovering chemical composition
in a structure.
Fix argument passing of the docstrings for Lattice and Structure properties.
Ignore generated files.
Use git-based version definition.