merged branch m0ppers/master (PR #3184)

Commits
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b177786 Make twig optimizations configurable

Discussion
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optimizations not configurable

Valid option for twig but missing in the configuration. I am currently hardsetting this in my own bundle.

src/Symfony/Bundle/TwigBundle/DependencyInjection/Configuration.php

@@ -122,6 +122,7 @@ class Configuration implements ConfigurationInterface
                 ->scalarNode('debug')->defaultValue('%kernel.debug%')->end()
                 ->scalarNode('strict_variables')->end()
                 ->scalarNode('auto_reload')->end()
+                ->scalarNode('optimizations')->end()
             ->end()
         ;
     }