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, 8 insertions, 0 deletions

diff --git a/diapositives.md b/diapositives.md
new file mode 100644
index 0000000..4604c75
--- /dev/null
+++ b/diapositives.md
@@ -0,0 +1,8 @@
+---
+title: Diapositives
+layout: page
+lang: fr
+ref: slides
+---
+
+{% include link-listing.html entries=site.data.slides kind="slides" %}