Merge branch '2.7' into 2.8

* 2.7:
  Using FQ name for PHP_VERSION_ID
  [Form] Fix \IntlDateFormatter timezone parameter usage to bypass PHP bug #66323
  Harden the debugging of Twig filters and functions
  bumped Symfony version to 2.7.29
  updated VERSION for 2.7.28
  update CONTRIBUTORS for 2.7.28
  updated CHANGELOG for 2.7.28

Author: fabpot

Encoder/JsonDecode.php

@@ -101,7 +101,7 @@ public function decode($data, $format, array $context = array())
         $recursionDepth = $context['json_decode_recursion_depth'];
         $options = $context['json_decode_options'];
 
-        if (PHP_VERSION_ID >= 50400) {
+        if (\PHP_VERSION_ID >= 50400) {
             $decodedData = json_decode($data, $associative, $recursionDepth, $options);
         } else {
             $decodedData = json_decode($data, $associative, $recursionDepth);