Forum software usage

Updated official centminmod.com site instructions to add Xenforo 2 configuration notes for Centmin Mod Nginx friendly url rewrite rules. Xenforo 2 nginx configuration adds an additional internal location context for /src/ directory not present in Xenforo 1.5.x nginx configurations. The instructions below have the /src location context commented out with instructions to uncomment it for Xenforo 2...