AP_Arming: param doc fixes

These were confusing the parser, or just incorrect
TradHeli: disable AutoTune for Tradheli compile

We need the flash space, and this probably won't work for tradheli anyway since tradheli needs most of the control from Feedforward rather than P term.  And D-term is very very bad.
TradHeli: enable Landing Collective when we are not moving

This prevents full negative pitch when touching down in Alt Hold or Auto-Landing.
TradHeli: rename Stab_Col parameters

With H_ prefix they appear with the rest of the tradheli specific params in the parameter list.
TradHeli: Minor change to two param defaults

Also one param name in the code clarified.
TradHeli: Drift mode to use heli manual throttle
AP_GPS: Improved accuracy of NMEA driver

The conversion of ret (32bit-integer) to float reduced accuracy to ~9cm or ~22cm. Now it's ~1cm.
Rover: try changing GPS setting to AIRBORNE_4G

this may reduce the GPS latency and improve chicane performance
HAL_PX4: fixed build for new PX4Firmware
Copter: disable OPTFLOW for PX4/Pixhawk
Copter: disable OPTFLOW for SITL
Copter: remove PID logging

Almost never used and eats up limited log description space
Copter: add time to ATT, MAG, CURR dataflash msgs
Copter: add TimeMS, InavAlt to CTUN df msg
Copter: combine NTUN and INAV dataflash msgs
AP_Notify: external LEDs blink while initialising
Rover: Fix SYSID ranges to support GCS display of param correctly
Copter: Fix SYSID ranges to support GCS display of param correctly
DataFlash: try to keep dataflash writes aligned

also rename lastlog.txt to LASTLOG.TXT as NuttX seems to get less
corruption with VFAT filenames that don't need uppercase mappings
Plane: use uppercase names on microSD card where possible