relax SVN archive

Redesigned get_intro_string() to return a container of different strings.

The method is now called get_intro_text() and returns a container with the following str objects:
- title: The program title 'relax'
- version: For example 'repository checkout' or '1.3.8'.
- desc: The short program description.
- copyright: A list of copyright statements.
- licence: Text pertaining to the licencing.
- errors: A list of import errors.

This is being abstracted so that the different UIs can use this differently. The prompt/script can
word wrap to 100 char (80 char in Windows), and print this to stdout. The GUI can use this in the
about prompt and not print to stdout. Other interfaces can use this in any other way. And the
information content can be expanded for different purposes.

Added the stub function maths_fns.order_parameters.iso_cone_S_to_cos_theta().

This will be used to convert the order parameter S into the cosine of the cone angle.

Added some menu separators to prettify the menus.

Completely redesigned the relax about dialog into its own widget using wx.PaintDC.

This works much better! Ideas from http://zetcode.com/wxpython/customwidgets/ were used.

Shifted the saved file name out of the relax data store.

This is a temporary variable and does not need to be stored or saved!

Fix for the selection of the model-free models to be optimised.

This problem was found by Michael in the thread starting at
https://mail.gna.org/public/relax-devel/2010-02/msg00004.html (Message-id:
<4B689504.2040601@...>).

Added a shrunken version of ulysses_shadowless.png with transparency.

Expanded the relax about dialog.

This includes concepts of size, background colours, boarders, binding left click events, and
building the core of the dialog. Most code is in the base class.

Comment fix in About_base.__init__().

Converted About_relax into the About_base base class, and added About_relax which inherits from it.