Update to Jekyll 3.0

[pbanaszkiewicz]

Changes:

• added a pagination gem

Maybe worth adding (cc @gvwilson):

• --incremental to jekyl serve (see https://github.com/blog/2100-github-pages-now-faster-and-simpler-with-jekyll-3-0#need-for-speed): first build of the site (make serve) took me 92s, second one 15s
• profiler - for testing (see link above)

Noticed changes:

• blog categories aren't lowercased anymore (ie. 'amy' became 'AMY')

All in all it seems like pretty easy migration; I'll upgrade the server's version once this is merged.

This fixes #211.

[pbanaszkiewicz]

The strange behaviour from #210 does appear in my build:

• newly added post triggers jekyll rebuild, but the post doesn't show up
• it was necessary to rerun jekyll serve (make serve) - then the post showed up