Apply mask before checking string length to see if entire message is received
Apply mask before checking string length to see if entire message is received

Resolves issue #16, where multi-byte encoded messages were sometimes reporting a length less than the length reported by the message's headers.  Applied to non-mbstring logic branch for consistency.
jerinho/PHP-Websockets,philek/PHP-Websockets,jahanzaibbahadur/PHP-Websockets,philek/PHP-Websockets,ghedipunk/PHP-Websockets,jahanzaibbahadur/PHP-Websockets,sjw-github/PHP-Websockets,kofidazy/PHP-Websockets,jerinho/PHP-Websockets,Xaraknid/PHP-Websockets,sjw-github/PHP-Websockets,Xaraknid/PHP-Websockets,zjsxwc/PHP-Websockets,kofidazy/PHP-Websockets,vinod1988/PHP-Websockets,zjsxwc/PHP-Websockets,vinod1988/PHP-Websockets,ghedipunk/PHP-Websockets