[RFC] strict_requirements = null on production
merged branch cordoval/patch-2 (PR #529)

This PR was squashed before being merged into the master branch (closes #529).

Discussion
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[RFC] strict_requirements = null on production

implements changes proposed on and replaces #496

Commits
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dfdf783 [RFC] strict_requirements = null on production
Merge branch 'master' of github.com:symfony/symfony-standard into symfony-master

Conflicts:
	app/config/config.yml
	app/config/config_prod.yml