Resume DO_ commands (i.e DO_SET_ROI) when mission is resumed

[2015-10-09, 14:58:35] Bill Bonney: I just had a SITL mission with two ROI set, stop looking at the ROIs
[2015-10-09, 14:59:19] Bill Bonney: when I reuploaded the mission, no changes, it went back top looking at the ROIs
[2015-10-09, 15:00:13] Bill Bonney: And I can reproduce
[2015-10-09, 15:01:04] Bill Bonney: Just switch to Loiter (while in auto) then back to Auto.

I think this issue is related to the fact that when you 'pause' a mission by going to loiter and the ROI command has passed, it's not registered again until a new ROI command is encountered

I would have expected the mission behaviour to resume where I left off.

Reproduce the reported SITL mission by switching from Auto to Loiter and back to Auto after a DO_SET_ROI command has run. Trace mission-resume handling and DO_ command processing; done means the resumed mission preserves the expected ROI behavior instead of waiting for a later ROI command.

Written by the indexing model from the issue text.