relax SVN archive

The prompt UI help string construction code is now handling the new Uf_tables singleton.

Added a check to Uf_tables.get_table() to make sure that the table corresponding to the label exists.

Fixes to the calls to Desc_container.add_table() in some user functions.

Added a check to Desc_container.add_table() to make sure the label is a string!

All of the user function documentation tables now use the new Uf_tables singleton structure.

The special properties for the colour module tables (longtables and now spacing) have been added as
well.

Fix for the new Uf_tables.add_table() method - the table is now returned.

Created a new way of defining and inputting tables into the user function descriptions.

This introduces the user_functions.objects.Table for holding all the table data and metadata, and
the user_functions.data.Uf_tables singleton object for holding all the tables. This design will
allow more metadata (for example using longtables in the LaTeX user manual) to be specified. The
singleton collection of tables with unique labels will also allow the elimination of duplicated
tables in the PDF and HTML user manuals. The new table title metadata will also be used for the
table headings in the user manuals.

Converted a number of add_verbatim() calls to add_item_list_element() with items of None.

This allows for proper formatting and indentation of equations. In the future, a possible
add_equation() method might be added to provide text and LaTeX representations of equations in the
user function documentation.

Itemised lists without items are now supported in the prompt help strings.

This is to mimic the LaTeX behaviour to allow lists with no 'bullets'.

Shifted the prompt examples to the end of the description for the value.display user function.