Reformat scdrs perform-downstream --group-analysis (I haven't checked the other two)
Changes in scdrs.method:
Editted scdrs.method.downstream_group_analysis
Changes in scdrs.util:
Added function scdrs.util.str_or_list_like for determining the type of group_analysis using duck-typing (used in scdrs perform-downstream --group-analysis).
Changes in ./bin/scdrs
Changes in scdrs.method:
Changes in scdrs.util: