Add support for MAVLink .tlog formats

[Georacer]

Naturally, this is a completely new and separate format, justified only by its popularity and constant use with all things Ardupilot.

I think the best way to approach it is to create another generator Python script (see https://github.com/ArduPilot/pymavlink/tree/master/generator) which will produce MATLAB code (scrirpt/function/class) based on the up-to-date MAVLink definition. Then, the provided log could be parsed using that dynamic code.