Add pagination to blog posts page

[cristineguadelupe]

This PR solves #148

This should be seen as a temporary solution. I think it’s worth the price fix the access to the older posts as soon as possible even with a not so elegant solution. I will work on a more complete solution that allows readers to choose items per page, with pagination working with tags too, an improved and responsive design and a more organized code.

[doomspork]

@cristineguadelupe could you rebase on master to eliminate the conflicts?

[cristineguadelupe]

@cristineguadelupe could you rebase on master to eliminate the conflicts?

Done!

[kinson]

@cristineguadelupe I'll pull this down and check it out this evening!