<r:page:published_at /> needs a default value

[architarious]

<r:page:published_at /> doesn't appear to have a default/fallback value like <r:article:published_at /> does. If you're using conditional logic to parse anything by published date, it will break unless the user remembers to create a published_at: field within their mock-data file.

Examples for current mock-data workarounds:

• published_at: <%= Time.now %>
  OR
• published_at: "2017-08-14 13:47:19 -0400"

[zeroedin]

So this commit fix is currently in the test branch. This branch also brings vagrant and virtual box up to current versions. Will be testing this branch for a bit then moving it to dev. Then finally merging with master after a detailed Changelog is created. There were some modifications made in dev that changes things about mock_data defaults that people have to be made aware of.