Remove leftover submodule file
Remove leftover submodule file

See http://stackoverflow.com/a/4185579/2631715

whilesoftware/haxeflixel.com,joackobengochea/haxeflixel.com,gamedevsam/haxeflixel.com,whilesoftware/haxeflixel.com,whilesoftware/haxeflixel.com,gamedevsam/haxeflixel.com,gamedevsam/haxeflixel.com,joackobengochea/haxeflixel.com,IBwWG/haxeflixel.com,IBwWG/haxeflixel.com,joackobengochea/haxeflixel.com,IBwWG/haxeflixel.com