Custom attributes to th tags

[sharok]

Related to #204

I have tried the following template for adding custom attributes:

<script type="text/ng-template" id="localTemplateThead.html">
                        <tr>
                            <th test="test" ng-repeat="column in columns track by $index"
                                ng-class="classToShow(column)"
                                ng-style="::column.style" ng-click="sortBy(column)">
                                Custom <span ng-bind="::column.name"></span>
                                v/th>
                        </tr>
                    </script>

But I don't see my test attribute.

[sharok]

I have found error. There are error in docs.
<thead tasty-thead template-url='"localTemplateThead.html"'></thead>

We need to use double quotes.

[Zizzamia]

@sharok do you wanna ask a PR for fix that?