Initial support for CPP code

[digitalentity]

C++ provides better code structuring if used carefully

[Linjieqiang]

Why do we need CPP code in this project?

[stronnag]

Dual licence by stealth (no I'm no really that cynical).

[digitalentity]

@Linjieqiang CPP allows writing simpler code in many cases. @stronnag for scope of this project it's still GPL, it just allows me to re-use dual-licensed code in non-GPL projects without need to go through "rewrite/relicense" fuss.

[stale[bot]]

This issue / pull request has been automatically marked as stale because it has not had any activity in 60 days. The resources of the INAV team are limited, and so we are asking for your help. This issue / pull request will be closed if no further activity occurs within two weeks.

[JulioCesarMatias]

I miss that in iNav... If all .cpp and .h extensions had "Class", everything would be much nicer visually, and more organized.