added droneshare conversion rate to the google analytics.
added analytics to track the number of mission files saved.
measuring the missions created and sent to the drone.
added analytics to measure usage of the flight action buttons, and flight mode selector.
added analytics for autopilot warnings.
code cleanup.
Merge pull request #1180 from ne0fhyk/analytics_update

Analytics update
Merge branch 'master' of https://github.com/DroidPlanner/droidplanner into compassCalibration