Update to Symfony 3.2.4 and start supporting Twig 2

Author: bocharsky-bw

composer.json

@@ -27,7 +27,7 @@
         "symfony/swiftmailer-bundle"           : "^2.3",
         "symfony/symfony"                      : "^3.2",
         "twig/extensions"                      : "^1.3",
-        "twig/twig"                            : "^1.28",
+        "twig/twig"                            : "^1.28 || ^2.0",
         "white-october/pagerfanta-bundle"      : "^1.0"
     },
     "require-dev": {