This new method name is consistent with the equivalent in the
AC_PosControl class

this will make it easier to analyse logs

too many people can't understand how to download .bin logs

this allows it to work with old style .log files

Log_Write_Baro should be an empty function when logging is disabled
Fix contributed by Jason Short

Based on original work by Nils Hogberg

Based on original work by Nils Hogberg

Based on original work by Nils Hogberg

Based on original work by Nils Hogberg

Based on original work by Nils Hogberg

Modified and integrated by Randy Mackay

Based on original work by Nils Hogberg

DisplayName isn't a description

this prevents us setting trim values under joystick control

- added MIS_AUTORESTART parameter, defaults to 0
- added start_or_resume() function to either start or resume a mission
based on that parameter value

Resolves issue #435
If the altitude fence is enabled, when the vehicle RTLs it will return
at the lower of the RTL_ALT and the FENCE_ALT_MAX

This resolves issue #880 in which if a GPS failsafe occurred while the
vehicle was already in LAND mode, the LAND would continue to be GPS
controlled LAND instead of pilot-controlled LAND

saves 2 bytes