Support constructors

[nmpolo]

Alice supports using constructors to generate fixtures as show here: https://github.com/nelmio/alice/blob/master/doc/fixtures-refactoring.md#usage-with-functions-constructor-included

This bundle currently does not allow fixtures to be generated to use the constructor and editing the fixtures manually to use the constructor would be a lot of work and goes against the principle of this bundle.

Can the bundle be updated to support the use of constructors? If so, how?