Add NULL pointer check to RooFitter.cpp
Use named ranges for fitting and fix NumCPU

Use the named range "plot range" instead of 50, 150 as the range for
plotting.

NumCPU is not a valid input to various functions, it has been removed
where it is invalid.
Switch to binned background model in RooFitter.cpp

Formerly we used RooKeysPdf which allowed unbinned fitting, but took a
very long time to initialize (many hours for the full background
sample). With binned fits the fit takes order of minutes.
Adjust Haupt Function parameter limits and ratio

alpha, gamma, and delta have new limits applied. The signal ratio is now
initialized near 1 (because it is the amount of signal expected) and not
near 0 (which I was doing because I mistakenly thought it was the
background fraction).