Update Drone_sensor_library.ino - WSchuler

[weschuler]

Addition of comments and questions to the code. Marked by WSchuler

[zbkitz]

Thanks for fixing the comments on the messages and publishers.
In lines 161 and 231, each case is a different "mode" for the system; each case is already labeled with the name of the corresponding mode in the line above each case statement (e.g. lines 162 and 232). Are you asking me to add a summary of the function of each mode?
I'm going to hold off on merging until you've had a chance to review the rest of the code.