Attention: flipped the yaw direction of multirotors in order to be compatible to APM
Merged with master
Merge pull request #138 from PX4/fix_yaw_direction

Fix yaw direction
Increased control_demo stack size.
Fixed minor compile error
Merge branch 'master' into fixedwing
Merge branch 'fixedwing' of git://github.com/PX4/Firmware into sensor_hil_fixedwing
Only predict if prediction window less than 1 second.