Created the relax_disp.nessy_input user function front and backends.
This user function takes the data in the relax data store and creates a NESSY save file to be opened
within NESSY. The backend is the new specific_analyses.relax_disp.nessy module. For the GUI
frontend, graphics for icons and the wizard have been taken from the NESSY repository file
pics/nessy_new.png@r1088 in the trunk.