Niki Lauda Tribute livery for McLaren P1

This is a v1.0 release of a Niki Lauda skin for Aige's McLaren P1. Unlike my other two skins, which were based on actual cars by MSO, this one was created from scratch. I welcome suggestions for improvement.

To install: Replace p1_sign_x with the included file. These files will be located within the .ytd of wherever you have installed the P1. For example, if you replaced the Infernus with the P1, then you would replace the sign files in the Infernus's .ytd folder.