Custom Lineshape Function
    This object is placed under a State object to allow an arbitrary position
      and quantum number dependent lineshape to be specified. There are
      some restrictions in its implementation; if the only state
      dependence come from varying lifetimes and thus a quantum number
      dependent Lorentzian see Custom
        Width Functions. Note that the current implementation has
      some restrictions in using these as part of a fit.
    
    Built In Variables
    The variables listed below are specific to custom lineshapes; all
      the variables in Custom Width
        Functions are also available.
    
    
      
        
          | x 
 | The distance from the line centre; in Mixture units 
 | 
        
          | Frequency 
 | The calculated line centre in
            Mixture units | 
        
          | Strength 
 | The calculated line strength. 
 | 
      
    
    Settings
    
      
        
          | Active | If true, use this to calculate the lineshape of each level | 
        
          | nDebug | Set non zero to write information to the log window on
            each use |