Add licensing information

[Rémi Verschelde]

Hi there,

Thanks for putting this up. Could you add a license so that Godot developers know under which terms they can reuse this code? If you want it permissive, MIT would likely be a good match.

[Pavel]

Should I put MIT header in each file, or LICENSE.md is enough?

[Rémi Verschelde]

Usually LICENSE.md is considered enough.