add “last_tag” to version information (e.g. 0.5.10)
Add Versioned_home, to help dynamically point to versioned releases

[#64338690]

https://www.pivotaltracker.com/story/show/64338690
Lab.config.get_versioned_url will return a versioned URL for interactive

[#64338690]

if the given interactive / embeddable is being served from a server that
knows its ‘versioned_home’ (see config.yml) then this method will return
the full URL to the versioned version of the interactive.

https://www.pivotaltracker.com/story/show/64338690
getVersionedUrl mv to common/url-helper.js. Add params for loading data.

[#64338690]

The methods for returning a versioned URL have been moved out to a helper.

The helper lets you add parameters to indicate things like try to load
learner data (so the initial interactive data isn’t loaded). And to allow
the interactive to display an warning / alert if the data won’t be saved.

https://www.pivotaltracker.com/story/show/64338690
Merge branch 'master' into versioned_urls

* master:
  add redirect handling