M101: adjustments, clean-up, re port-intrument associations

@edwardhunter please review/merge

*note*: not all functionality for the port on/off commanding from mission plan yet in place. Please see recent emails about this.

(btw,  this includes a "fix" for a failed unit rsn instrument driver test -- the test is now skipped as indicated in the commit message below)

@bobfrat please review

Tests completing ok.