better options parsing. 1) rida/meds are mutually exclusive, 2) -o defaults...

better options parsing.  1) rida/meds are mutually exclusive, 2) -o defaults step to last enabled step or last step option specified and 3) steps can only be on/off, not both  4) steps enabled multiple times are detected and a warning printed.  step order ignores all but first enabling of step


Former-commit-id: da7edac38e16f7537d73e4f9acce8cc1c838b2c3