LogSort: Add sorting by BRD_SER_NUM

[TunaLobster]

I'm not sure how well this works because I'm not able to get a VS environment set up.

The intent is to also sort log files based on BRD_SER_NUM. There are some uses for that parameter to identify what autopilot was used in which plane. Changes or other ideas are welcome. Maybe SYSID-SER_NUM format?

[AppVeyorBot]

:white_check_mark: Build MissionPlanner 1.0.3000 completed (commit https://github.com/ArduPilot/MissionPlanner/commit/8dfed58b37 by @TunaLobster)

[meee1]

so the concept is good, the issue is that this is only changing the sitl logs atm, ie to really be usefull needs to include the others as well. i would also add a check for "0" to exclude it

[AppVeyorBot]

:white_check_mark: Build MissionPlanner 1.0.3076 completed (commit https://github.com/ArduPilot/MissionPlanner/commit/f1e2c413bf by @TunaLobster)

[TunaLobster]

@meee1 I'm struggling a little bit to get this working in practice. Comments on what I am doing with the code would be helpful. Trying to learn a bit as I go.

[magicrub]

This is a great idea!