- this helps tease apart the various pieces of commander.

_uorb_topics_list was marked as 'const char *' array, which means the data
of the array was not actually const and thus landed in the data section
(so in RAM instead of FLASH).
The size of the array is 436 bytes.

_default_tunes was marked as 'const char *' array, which means the data
of the array was not actually const and thus landed in the data section
(so in RAM instead of FLASH).
The size of the array is 64 bytes.

This brings Gazebo 9 compatibility.

 - indent field print with tabs instead of spaces
 - print a newline before printing a nested field
 - cmake add generator dependencies

 - don't ignore position_setpoint_triplet

 - test values entered from https://www.ngdc.noaa.gov/geomag-web/

In commit
eb67686b
the TPA scaled integral gain was reverted back to the
normal unscaled gain which rendered the I part of TPA
useless.