Resetting mu range to low/high before initial fit (previously it would have been at mu_f+/2.5sigma from previous toy
Several tweaks for fitting before performing scan
 -> Moving to bkgfit for mu>0 (ie dont reprofile with signal in)
 -> Adding decomposition plots of pulls for each truth function
 -> Cleanup of nll curves before trying to determin pull (spike removal etc)
and fallback solution for pulls > range of scan
Merge pull request #356 from nucleosynthesis/nckw-tweaks-for-pulldefs

Nckw tweaks for pulldefs