Adds implied string formats to lua

ImpliedStringFormat.lua

-- Makes the module operator (%) between a string and a table behave like string.format
-- This works by setting the string metatable __mod function.
-- Example use:
--    str = "Hello %s, %d as hexadecimal is 0x%.2X" % {"world", 127, 127}

local mt = getmetatable("")
assert(mt, "string has no metatable")
mt.__mod = function(a,b)
	if (type(a) == "string") and (type(b) == "table") then
	  return a:format(unpack(b))
	else
	  return error("attempt to perform arithmetic on a string value")
	end
end