List for main-navigation

Hey guys, I am proposing to remove li in front of the current_page_item and current-menu-item. It's slightly more efficient without and of course all works the same :)
Merge pull request #351 from emiluzelac/patch-7

List for main-navigation
Make date formats translatable

Following up on a similar change to 2014, make the date formats for monthly and yearly archives translatable.
Merge pull request #352 from sabreuse/patch-1

_s: Make date formats translatable.
Merge branch 'master' into ja

* master:
  Make date formats translatable
  List for main-navigation