relax SVN archive

relax icon is not shown in "Global relax settings" window if running on a Mac.

This is as in revision 12856:
http://svn.gna.org/viewcvs/relax?rev=12856&view=rev),
but for the button "Settings" / "Global relax settings".

This change creates a bug, as the opened window upon clicking this button,
when closed, will have relax gui crash (with no button responding). This
needs to be fixed...

On the download page, added some instructions for the installation of wxPython under Mac OSX.

Abstracted the grid GUI element by renaming self.peaklist to self.grid.

Renamed peak_list_header() to add_header().

Shifted the grid construction code into the add_grid() method.

Shifted the button code into the add_buttons() method.

Fixed an alignment.

Better behaviour for the addition of peak list files to the Rx grid element.

Implemented the deletion of cell contents in the wx.grid element for Rx peak lists.

This requires a complex algorithm for handling wx.grid selections!

Added full size images of screen shots.