Copter: adjust autotune P and D min and max
Copter: autotune bug fix for restarting tuning from suspended state
Copter: autotune restore orig pids if user changes flight mode
Copter: autotune log when limits reached
HAL_SITL: decrease wind with altitude

this prevents JSBSim crash on the runway
AP_Baro: prevent a race condition in the SITL baro driver
autotest: report initial and final altitude in alt hold tests
Plane: changed to 2.75beta4
Copter: OctaQuad H-frame support
Copter: autotune to use 2pos switch only

method of recording state also changed
other code clean-up
pair programmed withe Leonard
Copter: enable AUTOTUNE by default
Iris: Updated Pitch parameters and added IMU logging
HAL_PX4: fixed a scheduler bug that affects UART IO

we need to detect if we are in a timer task using a PID, not a
flag. This is the same type of bug I fixed last week, but now fixed
properly.

The bug could well be the "USB bug" that Craig has been chasing
AutoTune: bug fix and GCS messages
Copter: bug fix to convert old batt params to BATT_ lib
sensor hil fix
Copter: Correctly set limit.lower flags for Tricopters

Resolves #536
Copter: autotune set original gains on reset

Update from Leonard
Copter: autotune bug fix for starting autotune

log completion to dataflash
Copter: slow start motors from 0 to min throttle