Multiple ressources not working, dead ends in documentation

[Lyso95]

I am reading through your documentation, must say it is frustral sometimes...

One example: https://github.com/BabylonJS/Extensions/blob/master/SceneManager/readme.md https://github.com/BabylonJS/UnityExporter/tree/master/Manager

there are multiple other ressources, which are going to dead ends "404 ERROR"

[deltakosh]

cc @PirateJC

[PirateJC]

@Lyso95 thanks for flagging this. We'll do a cleanup of the dead ends in the docs.

cc @RaananW