Add option to set names for RPKM columns in DESeq results file

[michael-kotliar]

Function get_deseq_job should return job file with untreated_col_suffix and treated_col_suffix fields.
DESeq DAG should be triggered with

conf = {"condition": ["untreated_uid", "treated_uid"],
        "rpkm_suffixes": ["_WT", "_KO"],
        "groupby": "isoform",
        "result_uid": "uid"}