remove the rs50* tutorials

tutorials/roostats/rs500a_PrepareWorkspace_Poisson.C

...oostats/rs500b_PrepareWorkspace_Poisson_withSystematics.C

tutorials/roostats/rs500c_PrepareWorkspace_GaussOverFlat.C

...s/rs500d_PrepareWorkspace_GaussOverFlat_withSystematics.C

tutorials/roostats/rs501_ProfileLikelihoodCalculator_limit.C

...roostats/rs502_ProfileLikelihoodCalculator_significance.C

...s/rs504_ProfileLikelihoodCalculator_averageSignificance.C

tutorials/roostats/rs505_HybridCalculator_significance.C

...als/roostats/rs506_HybridCalculator_averageSignificance.C