OMJSON can send invalid UTF8 strings

[sclaiborne]

This code checks for invalid whitespace but can still be invalid UTF8. Websockets as text must be utf8.

		// Check for invalid whitespace characters
		if (*ptr < 32 && *ptr > 0 && !(*ptr >= 8 && *ptr <= 13 && *ptr != 11)) {
			length = stringlcpy(pDest, "Invalid String", maxLength+1);
			length = length > maxLength ? maxLength : length;
			return length;
		}

Example failure:

0xFF 0xFE