Allow validations in before filter

[dprice-fiksu]

Addresses issue #168, 'validators executes after before_filter'. Adds the ability to call APIpie validations as a before_filter, instead of by wrapping the controller method (but preserves the old behaviour as the default).

[iNecas]

Thanks for this. Looks good at the first sigh. It would be nice to have there also :implicit option or something like that, that would use the before_filter, but being turned on by default: as a migration path from the old style, that I would expect to get deprecated soonish.

Waiting for green tests.

[dprice-fiksu]

I'll have a look at the :implicit idea. Unfortunately this is for the moment a spare time project and only gets worked on irregularly.

[dprice-fiksu]

I'm done changing this now, please take another look.

[mtparet]

👍 to use before_filter
I think it should be also good to let the user include/extend Apipie in which controllers he wants.
(Instead of loading it everywhere https://github.com/Apipie/apipie-rails/blob/master/lib/apipie/railtie.rb#L5)

[iNecas]

Thank you very much for your time, merging now

[iNecas]

I'm happy to announce that the new version 0.3.0 was released, including this change. Thanks for making that happen https://github.com/Apipie/apipie-rails/blob/master/CHANGELOG.md#v030