SurveyData - EnableCamTrigger

Add an option to enable/disable camera triggering option
SurveyData - cam trigger command implementation

add 2 additional commands
1. a SET_CAM_TRIGGER_DIST with a  distance of
LongitudinalPictureDistance before the survey points
2. another SET_CAM_TRIGGER_DIST with the value of 0 after the survey
points

these 2 command will enable the camera triggering signal on starting
the survey and disables it once the survey is done.