Modified add_stops so that datasets with null branching ratios will not be
processed at all. Also modified source_stop_ctau so that lifetimes <= 0.1 mm
will simply use the 1 mm datasets.
Updated the names of some of the displaced SUSY samples.
Changed the number of jobs for the displaced SUSY signal samples to 100 so that
as many jobs as files are launched.
Added a few variables relating to R-hadrons.