- I left derivative as undefined. Thus, the "Simplex" algoritm
   is used. Test minimization takes less than one second

- helper functions initXnlCoeff, initAlphaCoeff, initLinJlist,
         LorentzianCoefficients

 - lookup tables alpha and linearJlist.
 - numerical interpolation when close to numerical divergence
   for factor J.

and some minor enhancements.

The old one was back to front.

Actually there are tests which should test main logic. Not fully comprehensive, but enough for the time being.

A bit more tests would be useful.

reflected in gui and in algorithm itself

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>

The previous commit (dd887c97) actually won't help because TofEvent is not
movable (it uses composition). This change does, though only gcc implements
it so far.
That's the theory, but I have to admit I can't see a difference in run time.
Re #4472, Re #4779.

Allows overriding via the cmake variable, if desired.