Several improvements to enhance performance of fit and accuracy of fit results:
- accuracy:
   - ensuring homogeneous parametrization of FSE shape
   - enlarged accessible range for signal yield (important for finding the minimum)
- performance:
   - added option to fix boundaries for MC after initial OF fit
   - accepting covariance matrices that are not positive-definite but accurate
   - skip plotting for toys

note that there are still a few pre-processor macros calls around to zero in on a potential remaining issue.
Merge branch 'master' of https://github.com/MarcoAndreaBuchmann/CBAF