Revert php://temp to tmpfile().

php://temp was a good idea regarding performances but the stream content
is no more accessible from its name.

Author: Hywan

Stringbuffer.php

@@ -117,7 +117,7 @@ public function __construct ( $streamName = null ) {
      */
     protected function &_open ( $streamName, \Hoa\Stream\Context $context = null ) {
 
-        if(false === $out = @fopen('php://temp', 'r+'))
+        if(false === $out = @tmpfile())
             throw new Exception(
                 'Failed to open a string buffer.', 0);