Update GIFParse.php

Line 175:
$this->get8BitStringFromBinaryString
Library::get8BitStringFromBinaryString

Line 184
   protected function readBytesByLength($length) {
      $i = 0;
      $string = null;
      while ($i < $length) {
         $char = $this->fileobject->fgetc();
         if ($char === false) {
             throw new \Exception('Malformed GIF');
         }
         $string = $string . $char;

         $i++;
      }
      return $string;
   }