Merge branch '2.7' into 2.8

* 2.7:
  Set the redraw frequency at least to 1. Setting it to 0 would otherwise produce an error.
  [Process] Unset callback after stop to free memory
  Improve error message for undefined DIC aliases
  [VarDumper] fixed .sf-dump z-index
  [DependencyInjection] Validate class names and factory methods
  ampq → amqp
  Fix typo
  CS: remove unneeded parentheses around control statements
  [TwigBridge] Clean deps now that 2.8.0 is tagged

Author: stof

Iterator/SortableIterator.php

@@ -55,15 +55,15 @@ public function __construct(\Traversable $iterator, $sort)
             };
         } elseif (self::SORT_BY_ACCESSED_TIME === $sort) {
             $this->sort = function ($a, $b) {
-                return ($a->getATime() - $b->getATime());
+                return $a->getATime() - $b->getATime();
             };
         } elseif (self::SORT_BY_CHANGED_TIME === $sort) {
             $this->sort = function ($a, $b) {
-                return ($a->getCTime() - $b->getCTime());
+                return $a->getCTime() - $b->getCTime();
             };
         } elseif (self::SORT_BY_MODIFIED_TIME === $sort) {
             $this->sort = function ($a, $b) {
-                return ($a->getMTime() - $b->getMTime());
+                return $a->getMTime() - $b->getMTime();
             };
         } elseif (is_callable($sort)) {
             $this->sort = $sort;