mashephe/AmpTools: Version 0.15.0

This new version now supports the ability for users to write a customized contribution to the calculation of -2 ln( L ). (Thanks to Nils Huesken for developing this capability.) Users can create a class that inherits from Neg2LnLikContrib in much the same way that user Amplitude classes are created. This contribution is then initalized with a neg2LnLik keyword in the config file and parameters can be included. This may be useful to use external data, e.g., published data with errors, to provide additional constraints on parameters in the context of the main unbinned likelihood fit. An example is included with the Constraint class in the Dalitz tutorial. Additionally, a script is now provided in the ROOT directory that will load a subset of AmpTools modules into ROOT. Of particular use are the FitResults and ConfigurationInfo objects. Finally, the only other significant functional change is that when parameters are reinitialized or randomized (using the AmpToolsInterface) an underlying call to MNRSET in Minuit is made. This forces MINUIT to redetermine step sizes in minimization. This may lead to better outcomes when repeated fits are performed with randomized parameters