Support W3 Validation

[kmturley]

Great plugin! I found an issues using w3 validation when using the element syntax:

<js-tag></js-tag>

This also doesn't work if there was a JavaScript error on the page the input wouldn't show. A better method would be to do the following:

<label for="tags">Tags</label>
<input id="tags" type="text" placeholder="Enter tags (separated by commas)" class="js-tag" />

The update your directive to have restrict = 'c' and replace = true to replace the input with class="js-tag":

jsTag.directive('jsTag', ['$templateCache', function($templateCache) {
    return {
        restrict: 'C',
        scope: true,
        controller: 'JSTagMainCtrl',
        replace: true,
        templateUrl: function($element, $attrs) {
            var mode = $attrs.jsTagMode || "default";
            return 'jsTag/source/templates/' + mode + '/js-tag.html';
        }
    };
}]);

This validates as html5 compliant and provides a working input field if the library where to fail for some reason!

Additional features could be:

• Grab the placeholder text from the input field, for your tags text
• Apply an option to only load the directive on desktop computers vs mobiles

[eranhirs]

Thank you for your contribution.
Removing jsTag as a custom tag is not an option, but adding support for jsTag via attributes is welcome. I would like you to open a PR for this change.