relax SVN archive

Missing import.

Import fixes for the structural object module rearrangements.

Total elimination of the ScientificPython PDB object.

Maintaining this reader was too much effort and the internal structural object has now surpassed
the capabilities of the ScientificPython PDB object (for example the internal object is not PDB
specific). And ScientificPython is very much a dead project, largely replaced by the more
successful scipy.

Import fix form the previous commit.

Shifted the lib.structure.rotor module to lib.structure.represent.rotor.

Created the empty lib.structure.represent package.

This will be used to hold modules which generate 3D structures as geometric representations of
abstract ideas such as tensors, cones, frames, etc.

Shifted the MolContainer class from pipe_control.structure.internal into lib.structure.internal.molecules.

This is in preparation for shifting the internal structural object to lib.structure.internal and for
the elimination of the unused and no longer useful ScientificPython structural object.

Shifted part of the internal structural object into the lib.structure.internal.molecules module.

This contains the class MolList from the pipe_control.structure.api_base module.

Shifted part of the internal structural object into the lib.structure.internal.models module.

This contains the two classes ModelList and ModelContainer from the pipe_control.structure.api_base
module.

Created the empty lib.structure.internal package for holding the internal structural object.