As per issue #9428, this code change locks down the termios configuration
for the UART to non-canonical, binary tx/rx, 8 bits, 1 stop bit, no parity.

- genmsg in PX4/Firmware (3ed093ba): https://github.com/ros/genmsg/commit/3cea1fe528cd7ecdae7f8930fe90451271aec937
    - genmsg current upstream: https://github.com/ros/genmsg/commit/a189fc78558e7276df59d2961cfe4f8b4de08a8b
    - Changes: https://github.com/ros/genmsg/compare/3cea1fe528cd7ecdae7f8930fe90451271aec937...a189fc78558e7276df59d2961cfe4f8b4de08a8b

    a189fc7 2018-05-01 Dirk Thomas - 0.5.11
c641725 2018-05-01 Dirk Thomas - update changelog

 - px4_add_module now requires MAIN
 - px4_add_library doesn't automatically link

 - this flag often results in hiding useful information, or adding
   useless information to the mavlink console

Switch to the high latency telemetry, if available, if every low latency link is lost. Switch back if any low latency link is regained. Only indicate that all links are lost if all high and low latency links are lost. Allow different timeouts for high and low latency links.

Allow enabling/disabling transmitting data from all mavlink instances
with a specific mode/type. When disabled the instance can still receive
data. The uORB message used is the vehicle_command and uses the following
parameter:
param1: Specifies the mode/type of the instances to enable/disable transmitting
param2: Boolean to indicate if transmitting should be enabled or disabled

_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.

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

- true airspeed innovation and variance
- sideslip angle innovation and variance

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

The indexes are directly mapped from MAVLink, thus the actual value is
important.

If the EXTERNAL_MODULES_LOCATION variable has been set, and the
EXTERNAL_MODULES_LOCATION/msg/ directory exists containing a
CMakeLists.txt file with the following format:
    set(config_msg_list_external
      message1.msg
      message2.msg
      message3.msg
      ...
      PARENT_SCOPE
      )
then the messages defined in config_msg_list_external are added to the
msg_files list in Firmware/msg/CMakeLists.txt and are used to generate uORB
message headers. The generate uORB message headers are generated in the same
location as the normal uORB message headers in the build directory, namely,
<build_dir>/uORB/topics. The uORB topic sources are generated in
<build_dir>/msg/topics_sources.

* Updated and expanded batt_smbus to work with bq40z50-R2. Expanded battery_status.msg. Fixed mavlink_messages.cpp temperature, added commented out expanded battery_status.msg parameters for future mavlink expansion.

* Changed errx to PX4_ERR

* Added PX4_ERR returns

 - vehicle_status_flags condition_global_velocity_valid is also unnecessary

This adds a define for the tune strength instead of hard-coding it with
a magic number.

Don't use ADSB messages with undefined fields in navigator