relax SVN archive

Bug fix for the pymol.macro_apply user function - the command history is now cleared.

Without this, previous macro files will be executed, but if they were temporary and no longer exist,
then pymol fails.

Fix for the execution of pymol macros via the pymol.macro_apply user function.

The PyMOL commands are now written to a temporary file and this file is executed via the @x run
syntax. The PyMOL commands sent into the interface are asynchronously processed so that executing
a macro in that way always fails. However the commands in a *.pml macro file are processed
synchronously, eliminating the annoying bug.

Fixes for the user function docstrings for the changes to the macro modules.

The Molmol and PyMOL classes are now initialised by the model-free class and the methods aliased.

Added the macro_base module to the __all__ package list.

All the model-free macro methods are no longer private.

The class will not be used as a base class for the model-free specific class.

Added module docstrings for all the model-free macro modules.

Removed unused imports.

Abstracted the model-free 'classic' Molmol and PyMOL creation in to a base class.

As most of the code between the specific_fns.model_free.molmol and specific_fns.model_free.pymol
modules is identical, this significantly simplifies the code base.

Completely converted the PyMOL model-free macro creation from Molmol to PyMOL commands.

This now reproduces the Molmol 'classic' representation.