Work in progress.

 -Article and edit preview html no longer goes over javascript bridge.

 -Switched to single query article download - the reason is it
  is tricker to be splitting lead/non-lead section retrieval
  across 2 requests and also if the point of this refactor is
  to streamline away low-performance javascript, it seems
  antithetical to be amending/injecting late arriving
  non-lead section html via javascript. Additionally,
  now that we're using gzip encoding properly the download
  is much smaller than it was when we first split the
  request in 2.

 -Moved audio tag hiding out of transforms since they didn't
  work anyway - instead hobbled the audio tags before the
  html is sent to the web view, which does work.

Change-Id: Ie5aa09d7ac36f06930ac1bfbe09c0259240253fe