Remove format whitelist for read only Lua IO and allow more formats.

Full current whitelist:

	".dat",
	".bin",
	".bmp",
	".png",
	".obj",
	".json",
	".yaml",
	".xml",
	".csv",
	".soc",
	".cfg",
	".ini",
	".txt",
	".log",
	".md",
	".sav2",

io.open and io.openlocal (in r and rb modes) now can read file suffixed by any extension.