Changed some parameters on directive to make their values dynamic.

[willian]

In my app I have 3 environments: development, staging and production. Is common to have something like this, and use environment variables or a configuration file per environment to manage some data, like services API's IDs, secrets keys, etc.

Passing only string

<oauth site="https://instagram.com"
       client-id="'some-id'"
       redirect-uri="'http://example.com/callback/instagram'"
       scope="basic"
       text="Connect Instagram">
</oauth>

Using an object

<oauth site="https://instagram.com"
       client-id="OAuthInfo.instagramAppID"
       redirect-uri="OAuthInfo.redirectURL + '/instagram'"
       scope="basic"
       text="Connect Instagram">
</oauth>

Because of that I changed some parameters to allow me to send a object/variable instead of a plain string.

For now I'm using my own repository, but would be nice to use the original again.

Please, let me know your thoughts about this PR.

[andreareginato]

Would be great to have the following:

• tests with strings and variables
• docs on gh-pages

Can you make it @willian?

[andreareginato]

Any possibility to have a test suite on this @willian? It would be really a really nice to have feature.

[MikeSam]

+1 for parameters on directive

[bramski]

Poke @willian. This PR should be closed otherwise. It's looking rather ancient.