relax SVN archive

Missing import of the sys module.

Added some special RelaxErrors for data pipe bundles.

Added some bug catching code for the observer objects.

In some rare cases a registered method's key was set to None. This is now caught and a RelaxError
thrown to prevent later indecipherable errors.

The setup.py application building script now complains if the Python setuptools are not installed.

Import fix for the relax GUI tests for a problem only recently introduced.

Fix for the relax user manual compilation.

The full path for an icon in the graphics directory was being used.

Updated the relax prompt mode figure in the intro chapter of the user manual to the more modern prompt.

Improvements to the API documentation compilation.

The excluded files and directories, as well as hidden ones, are no longer included in the list of
files/directories to add to the documentation.

API documentation fix - a circular import has been broken.

This was only a circular import when the gui package is imported from an external program like
Epydoc.

Fix for the API documentation for the rename of the 'scripts' to 'devel_scripts' directory at r17708.