Fix #135 Invalid HTTP request headers in non-cURL

Thanks to @Fearitude for spotting this bug.

Author: mynetx

src/codebird.php

@@ -744,6 +744,9 @@ protected function getNoCurlInitialization($url, $contextOptions, $hostname = ''
             array('http' => $httpOptions)
         );
 
+        // concatenate $options['http']['header']
+        $options['http']['header'] = implode("\r\n", $options['http']['header']);
+
         // silent the file_get_contents function
         $content = @file_get_contents($url, false, stream_context_create($options));