Merge pull request #11 from onema/master

Updating develop
Removes code that wasn't used nor documented in the parameters.yml.erb file. The to add the values that where removed simply add them to the parameters list under `[custom_env][app_name][parameters]`.
Merge pull request #12 from onema/develop-paramConfig

Removes unused code
Adding an option in the `symfony::configure` recipe to execute the command `php app/console cache:clear --env=prod --no-debug` if the `warmup_cache` option is **defined** in the application configuration.
correcting syntax error
Update composer install command to prevent installing from source. If file is not available from zipball latest versions of composer should re-try from source.
update recipe
Merge pull request #15 from onema/develop

Symfony Cache Warm-up. Tested backwards compatibility, it should have no breaking changes.
Update README.md
Merge pull request #16 from onema/develop

Update README.md
Merge branch 'master' of https://github.com/onema/opsworks-chef-cookbooks