* add respawn_gazebo arg to be used with empty_world.launch
* catch rospy sleep method's exceptions
* fix copy-paste mistake in land state failure message

 - fixes #8828

	- ulog files are skipped from the analysis, if a corresponding .pdf file already exists
	- an overwrite flag can be set to analyse all the files

the FTPS client and agent.

A table has been added to the FTPS client and agent code that correlates
the baud rate value with the encoding.

A function has been added to the FTPS client and agent to take the program
argument for baud rate and use it to look up the table and return the entry
containing both the value and the encoding.

The value is displayed for the user and the encoding is sent to the uart
node constructor.

Signed-off-by: David Riseborough <drisebor@hotmail.com>

- Move check to proper location, out of the try catch block for OTP.
- Add Pixhawk specific check to notify users that want to flash
  px4fmu-v3_default on Pixhawks with older v4 bootloaders that do not
  support the silicon errata check.

This fixes the error below when using Python3:

  File "Tools/px_uploader.py", line 128, in
  __init__
      self.image.append('\xff')
      TypeError: an integer is required

 - currently doesn't work on all boards...

* Revert "mavlink_mission: don't retransmit automatically"

This reverts commit 4e008fe89120e24e321e93fb551753242797f022.

* mavlink_mission: don't retry to send mission item

The mission items need to be requested one by one by a ground station.
This is a "pull" protocol and we should not retry to "push" the mission
items down.

If we do this we can trigger the situation where the autopilot keeps
retrying and the ground station does not time out because it keeps
receiving items (even though the items are the wrong ones).

* mavlink_mission: reduce retry timeout

When actively re-requesting lost mission items, we can be more agressive
and therefore lose less time when a mission item is lost on the way.

disable mavlink on aero telemetry if tfmini enabled and start on mavlink companion device for others (needs SYS_COMPANION to be 0)

Accidentally dropped in bad813e9

This is now required in the startup scripts