relax SVN archive

The user function data object is now imported into the interpreter.

Fix for the Uf_container.__mod_attr__ list.

Removed a duplicate argument.

Added the desc_short arg to the add_keyarg() user function container method.

This arg is used in RelaxErrors for when incorrect parameter are supplied.

Converted the entire of the 'pipe' module to populate the user function data structure.

Big improvements to the user function data container.

The changes are:
- More attributes are now accepted.
- Now only allowed attributes can be modified, to prevent programming errors.
- Docstring improvements.
- More keyword argument data can be input.

Shifted a check from the pipe.create front end to the back end.

Tests do not belong in the front end! And this is not compatible with the new user function design.

Removed the pipe user function class import and instantiation from the interpreter object.

This will be re-introduced later with a new auto-generation architecture, taking the info from the
user_function data object.

This should hurt!! Shifted the pipe module from the prompt to user_functions package.

This is in preparation for the full conversion of this user function class into the new
auto-generation design. relax will be broken for a while now!

Added a unit test for the contents of the user_function package.