Refactor i18n structure, remove layouts, add slides

Yep, this commit is too big big I didn't want to take the trouble of splitting
it now.

- _config.yml translation keys are now simetrical on the entitiy: articles,
pastebins, tils, slides, etc.;
- _posts were moved to _articles: the _posts collection had special treatment in
Jekyll which I wanted to avoid;
- the filtering of entries for the Atom feed is now done inside the
_includes/feed.atom file instead of every feed file;
- all entities are now dealt with using the pluralized name: articles,
pastebins, tils, slides. No more inconsistencies on the key names, they now
should only make sense as the translation value on the dictionary;
- add base reveal.js infrastruture, with Jekyll generating the listing page and
nothing else.

1 files changed, 3 insertions, 0 deletions

diff --git a/feed.slides.pt.atom b/feed.slides.pt.atom
new file mode 100644
index 0000000..96c6155
--- /dev/null
+++ b/feed.slides.pt.atom
@@ -0,0 +1,3 @@
+---
+---
+{% include feed.atom entries=site.data.slides kind="slides" lang="en" %}