Navigation SET_HEAD is reciprocal

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Create a mission with SET_HEAD
2. Fly the mission
3.

What is the expected output? What do you see instead?
For SET HEAD, the vehicle will point in the direct set by SET_HEAD, instead it 
points in the reciprocal direction.

What version of the product are you using? On what operating system?
2.4.0 r1729 on Mega2560

Please provide any additional information below.
See attached patch. Flight tested.

Original issue reported on code.google.com by jonathan...@gmail.com on 22 Dec 2014 at 3:22

Attachments:

• set_head.dif
• nm-300-120-sethead.mission