Changed strlen for binary data to take into account mbstring.func_overload

[pmxmatt]

The function strlen behaves differently when mbstring.func_overload is enabled for the strlen function.

This was causing the message sending to fail I've updated the code based on the comment from a user on the official documentation http://php.net/manual/en/function.strlen.php#54906 .

[duccio]

Hi, thanks but… latin1?

[pmxmatt]

Using latin1 forces it into single-byte mode.

I've tested this with both mbstring.func_overload on and off in environment and it is now counting correctly.

[lucabrunox]

What's the point of checking mbstring.func_overload if mb_strlen($aMessage['BINARY_NOTIFICATION'],'latin1'); does always the right job? It could be used in place of strlen always I guess.