get prev page and next url

To build right structure (for SEO) for paginated web pages, as stated here https://support.google.com/webmasters/an...3744?hl=en we have 2 options:

1. implement VIEW ALL page or
2. put rel="prev" and rel="next" meta info in page

I am using second option. I extended Pagination Library to get prev_url and next_url. 

I guess it would very helpful functionality for Pagination Library if you add functions to get prev_url and next_url