relax SVN archive

The maths_fns.relax_fit module is now stored in the dep_check module for the info print out.

Redesigned the spin loading wizard.

Now the starting screen allows the choice of the sequence.read, structure.read_pdb, and
structure.read_xyz user functions. If structural data is already loaded, then the option to use the
pre-loaded structures is also given (which skips to the structure.load_spins user function wizard
page).

Added the structure.read_xyz user function to the menus.

Created the Tools->System Information menu entry, which is simply the sys_info user function front end.

Created the GUI front end to the structure.read_xyz user function.

The relax controller now accepts Ctrl-A to select all text.

Fix for the relax controller find dialog on Mac OS X with wxPython 2.9.

The dialog Show() method now needs to be called. This should not affect wxPython 2.8 behaviour.

The relax controller now shows the relax intro text to mimic the prompt/scripting modes.

Previously the text was being printed prior to the initialisation of the controller and was being
lost.

Introduced the empty() method into the structure API to check if structural data is loaded.

This will be used in the spin loading wizard of the spin viewer window.

Converted the structure.read_xyz user function front end to the new design.

This will be used later for introducing this into the GUI.