Remove "Lightweight" from the title, as per: [#47150075]

Change lightweight authoring url from lightweight-mw.concord.org to authoring.concord.org, and change title that says 'Lightweight Activities' on the home page to 'Activities'.

https://www.pivotaltracker.com/story/show/47150075
Merge branch 'staging' into production

* staging:
  Remove "Lightweight" from the title, as per: [#47150075]