relax SVN archive

The R1 and R2 curve-fitting tabs are now also completely deactivated by the execution lock.

The NOE auto-analysis tab is now complete deactivated with the execution lock.

The about relax and about GUI menus were mixed up too!

The execute relax button is now turned off by the execution lock in the model-free auto-analysis tab.

Now all elements of the tab are deactivated.

add_execute_relax() is now actually returning the button.

The analysis base class add_execute_relax() method now returns the button.

Fixes for the handling of borders in the about dialogs.

Fix for the help menu - the about relax and licence menus were mixed up.

Fixes for the model-free auto-analysis about dialog.

Changes to the base class had broken this dialog.

The add_spin_systems() base class method now returns the Text_ctrl instance it creates.