Parse titles

Attempt to parse cell title titles before displaying them.

I'm using Angular-Translate and would like to have my table header titles filtered. This PR will have the directive attempt to run the Angular parser on titles before they're displayed. A user's markup would look like this:

```html
<table ng-table="tableParams">
    <tr ng-repeat="one in many">
        <td title="'FIRSTNAME' | translate">{{one.firstname}}</td>
        <td title="'LASTNAME' | translate">{{one.lastname}}</td>
        <td title="No parse run">{{one.hello}}</td>
        <td>Still works</td>
    </tr>
</table>
```