Topic structure enhance, add tab

[kmk]

Right now we have Topic thread plus Poll, request new structure for an enhanced purpose:

1. Topic content and their replies as a thread. This is first tab. 

2. Poll should be moved to second tab, but leaving a title as link in the topic title header. This poll will be second tab. 

3. Checklists feature should be placed in the topic threat as tab, this will be third tab. The title should be placed in the topic header as direct link too. New requested functionality. 

4. Custom field for Topic, this should be the fourth tab, this feature title should be placed in the topic header area too. New requested functionality.