Update archetypes (#305)

* Update archetypes to YAML

* Remove deprecated metaDataFormat

* Add Newline at the end

archetypes/default.md

-+++
-title =  "{{ replace .TranslationBaseName "-" " " | title }}"
-date = {{ .Date }}
-tags = []
-featured_image = ""
-description = ""
-+++
+---
+title: "{{ replace .TranslationBaseName "-" " " | title }}"
+date: {{ .Date }}
+tags: []
+featured_image: ""
+description: ""
+---

exampleSite/config.toml

 theme = "gohugo-theme-ananke"
 themesDir = "../.."
 
-MetaDataFormat = "yaml"
 DefaultContentLanguage = "en"
 SectionPagesMenu = "main"
 Paginate = 3 # this is set low for demonstrating with dummy content. Set to a higher number
   # choose a background color from any on this page: http://tachyons.io/docs/themes/skins/ and preface it with "bg-"
   background_color_class = "bg-black"
   featured_image = "/images/gohugo-default-sample-hero-image.jpg"
-  recent_posts_number = 2
+  recent_posts_number = 2