- fixes #10925

FlightTaskAutoLine: ensure that desired speed along track does not exceed maximum speed at threshold to target

Smoothing can be configured by MPC_POS_MODE parameter
put before only for position mode and not for altitude mode.

*  a request for setting the '_HASH_CHECK' parameter is handled differently
than the same request for a standard parameter. Make sure we don't actually
try to set the parameter.

Signed-off-by: Roman <bapstroman@gmail.com>

Co-Authored-By: CUAVcaijie <caijie@cuav.net>

You can now add `DYNAMIC` as an option to `px4_add_module`, which will
cause that module to no longer be compiled into the px4 executable, but
instead produce a separate shared library file, which can be loaded and
executed with the new `dyn` command:

    pxh> dyn ./hello.px4mod start

This will load the shared object file `hello.px4mod` if it wasn't
already loaded, and execute its main function with the given arguments.

The threads running commands for clients through the Posix daemon used
to write to a char buffer through snprintf (etc.) which was then written
directly to the file descriptor, whereas in the other case printf
(etc.) was used to write to stdout (FILE*). Both versions used some
macro's and repeated code to have the same output.

This change unifies these two cases by using a FILE* in both cases. The
(line) buffering is done by the standard C library's implementation
(just like with stdout), and px4_log.c now uses the same code in all
cases (using fprintf, etc.) for printing (colored) output.