Sync index*, config*, kernel and autoload file with Symfony-standard
Sync with Sf-standard 2.2 and enable composer post install/update scripts

Also moves SensioDistributionBundle & SensioGeneratorBundle to dev only, this will probably need some doc changes but might lead to slightly better performance in prod.
Add phpunit.xml.dist file from symfony-standard
Add ScriptHandlers for legacy & prod assets
Update doc to reflect assets being dumped by composer