relax SVN archive

Shifted the pipe_control.structure.internal module to lib.structure.internal.object.

This is the new location of the internal structural object.

Docstring consistency in the internal structural object.

Spacing fixes in the internal structural object.

Import fixes for the lib.structure.internal.displacements module.

Moved the residual pipe_control.structure.api_base module to lib.structure.internal.displacements.

This is because the base module still contained the Displacements class.

Updated the package __all__ list for some unit tests.

Deleted the unit tests of the structural API base class.

Merged the structural API base module api_base into pipe_control.structure.internal.

The API base class is no longer needed as the ScientificPython PDB reader has been eliminated.

Fixes for more missing imports into lib.structure.internal.molecules.

Missing import.