Fixed the block comments at the top of the source file and the help message for the script (starting at line 279) so that an underscore ("_") character is correctly described as the separator for the first message field name rather than a period character "."

This fixes the compass, see:
https://github.com/PX4/jMAVSim/pull/55

usage:
export replay_mode=ekf2
export replay=<abs_path_to_log.ulg>
make posix none

currently jmavsim uses a default rate of 500 Hz which is too much.

In order to use px_uploader as a module from another Python script, all
the action needs to be moved into a main() function which is only called
if the file is run directly.

Sometimes right after reboot, we got a `raise SerialException(
msg.errno, "could not open port {}: {}".format(self._port, msg))`.
If this happens now, we will just try again later.

Found by PEP8 checker.

This file had the indentending mixed up between 4 and 8 spaces.
This changes it to the Pythonic way of 4 spaces.

* Fix several valgrind identified mem leaks

* Added callgrind target.

* px4_posix_tasks use nullptr

We still want to be able to program the flight stack if the user changes
the baudrate of that UART.

We may need to change the baud rate from one version to the other.
Allowing the script to try multiple baud rates makes the transition a
little bit less painful.

This also fixes a bug in which it would go the next port before trying
to identify the board after asking it to reboot.

Fix typographical error

Refactored calibrator is not working.

The flight code assumes corrections have the same sign as the sensor bias error and are subtracted from the raw reading

* Added tool to restore defconfig sections after make [old|menu]config

* Use tool to restore defconfig sections after make [old|menu]config

   invocation:
      make px4fmu-v2_default oldconfig_px4fmu-v2
      make px4fmu-v2_default menuconfig_px4fmu-v2

* Streamline python script for temp cal.

* Simplify file generation for temp calibration.

* Fixed build error in Snapdragon Flight legacy driver mode (partially)

* Fixed build error in eagle_legacy_default mode (px4muorb.h generation issue)

* Fixed the snapdragon flight sanity test script (default and legacy driver modes)

* Fixed PX4 sanity test script (removed a check msg)

* Fixed build error in Snapdragon Flight legacy driver mode (partially)

* Fixed build error in eagle_legacy_default mode (px4muorb.h generation issue)

* Fixed the snapdragon flight sanity test script (default and legacy driver modes)