and make sure the command failed if there's a validation error.

use c++ so that raw string literals can be used

use c++ so that raw string literals can be used

when the fmu was already running in a pwm mode, changing to mode_rcin would
not have any effect.

It is not handled and not documented.

And turn it into a markdown page.
It also does some simple validation, to check that the getopt() arguments
match the documentation.

If called with ./Tools/px_process_params.py, the path would start with
src/<module>, and thus not match the regex "^.*/src/"

usage:
./px_process_airframes.py -m -i ../image/path

to keep the behavior the same, remove the -e flags from all pwm commands
that use it in the scripts.

Sorry for the large patch :)

- move cleanup into destructor (this was done on the wrong task before)
- move init into init() method
- sensor & peripheral reset do not start/stop fmu anymore
- remove err & errx (they do not release the lock and could lead to dead-
  locks)

g_port_mode was never changed.

Provides:
- thread-safety for module start/stop
- some shared code for module start/stop. Should also be less prone to
  errors.
- constructor & destructors are called from within the new module thread
- can be used for work queue & thread modules
- strutured & formal way for module printf usage & module documentation

Limitation:
- supports only modules with one instance (eg. not mavlink)

   This is part 2 of the fix. The tool that extracts the nuttx
   git tag was broken by a new tag added the did not match
   the form nuttx-M.mm. To the value was printed as

   OS: NuttX
   OS version: 0.0.0 c0 (192)

  Once that issue was fixed, it was apparent that recent
  changes to version.c return the values as base 10, before
  it was hex. This fixes the formatting.

  This is part one of a fix for cascading failure. The NuttX
  nuttx repos was tagged with upstream_7.18+ and broke the tag
  extraction that was expecting nuttx-M.mm

previously, get_devname() was used as the I2C device path, but on NuttX,
get_devname() is the device file which the driver creates. This patch
changes it, so the sematics are the same as on NuttX: both now use _bus
to decide to which I2C bus device to talk to.

I did not see any other use-cases than the led on ocpoc.