Adding support for invokable controllers to the ParamConverterListener
feature #333 Adding support for invokable controllers to the ParamConverterListener (jameshalsall)

This PR was squashed before being merged into the 3.0.x-dev branch (closes #333).

Discussion
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Adding support for invokable controllers to the ParamConverterListener

Invokable controller support was added to Symfony in https://github.com/symfony/symfony/pull/11193.

The problem was that the `ParamConverterListener` did not support passing an object as the controller, this PR adds that support.

Commits
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1b83587 Adding support for invokable controllers to the ParamConverterListener