Pagination - WIP

Closed last one by mistake. Works towards #15 
Things left to be done:
- [ ] Get value of "number of comments to be shown by default" from config
- [ ] Correct the value of total number of comments for the url (shown in `#isso-thread > h4`)
- [ ] Maybe show a loader icon when "Load More" is clicked
- [ ] Color/Design/Position of "Show More" link/button
- [ ] i18n for the text on "Show More" button
- [ ] Testing on 100s of comments or more