Added ARVR_Helpers script.

[Malcolmnixon]

This is a preliminary script related to issue #70 to help locate ARVR nodes.

I ended up not adding a function to look for the PlayerBody in here because it leads to circular dependencies. Instead my demo project adds the routine to the PlayerBody script:

    # Find the player body from our own node somewhere under the player
    var body := PlayerBody.get_player_body(self)

[BastiaanOlij]

Looks good, just need to find a nice way to make sure this is accessible. It should really be auto loaded, I wish there was a way to automate this.

[BastiaanOlij]

Ok, I never knew this. It used to be so that you had to autoload scripts to use them, but the combo of using class_name with static func will automatically load the script if you call the static function from anywhere else in the code. :)