* Fix for the software verification tests. The recent expansion and improvements of the REMARK records created by the internal structural object PDB writing method imported the relax version to place this information into the PDB files. However this breaks the relax library design, as shown by the verification tests. Instead the relax version information is being taken from the lib.structure.internal.object.RELAX_VERSION variable. This defaults to None, however the version module now sets this variable directly when it is imported so that it is always set to the current relax version when running relax.
* General Python 3 fixes via the 2to3 script.
* Removed the lib.compat.sorted() function which was providing Python2.3 compatibility. For a while now, relax has been unable to run on Python versions less than 2.5. Therefore there is no use for having this replacement function for Python <= ≤ 2.3 which was being placed into the builtins module.
* Python 3 fixes for the entire codebase using the 2to3 script. The command used was: 2to3 -j 4 -w -f xrange .
* The internal structural object add_molecule() and has_molecule() methods are now model specific. This allows for finer control of structural object.