fix(angular): do not launch the directive if autocomplete has a value

[Jerska]

Closes #136

Summary

As described in #136 , we're bugging out the behavior of the HTML autocomplete attribute.
You can't use autocomplete="off" in the current setup, this PR fixes it.

Result

Checked in test/playground_angular.html.
Attribute mode:

• autocomplete => our autocomplete triggers
• autocomplete="" => our autocomplete triggers
• autocomplete="off" => our autocomplete doesn't trigger and it correctly prevents the browser from autocompleting
• data-autocomplete => our autocomplete triggers

I've also checked that the class mode of the directive still works.

[coveralls]

Coverage increased (+0.01%) to 88.849% when pulling f96a1ba on fix/angular into be1dc19 on master.

[redox]

Why do we need to check the class ?

[Jerska]

Because of the restrict option used here: https://github.com/algolia/autocomplete.js/blob/f96a1bad72212066dab735de08d560cf6122f65b/src/angular/directive.js#L33

 restrict: 'AC', // Only apply on an attribute or class

[vvo]

Are browsers reporting the same value when you set <input autocomplete and try to get the autocomplete attr value?

Could we ensure this quickly on evegreen browsers and IE10+? I know this is hairy to do, a simple jsFiddle with an alert could do it and you launch it from saucelabs or smg else

[Jerska]

Confirmed in IE9 and Safari 6 (using a simple console.log(JSON.stringify(attrs.autocomplete)); and loading playground_angular.html in browserstack)
As soon as those two were confirmed, I didn't bother checking the rest.

[vvo]

Thanks a lot