GPII-147: don't convert model on init

No longer converting the model on init. What was happening is that due to the model transformation layer, if a change was saved and the page reloaded, it would be set and unset. This is because the model value for the enactor would be set correctly on init, but the preset models would then be set and transform the enactor models one at a time. To get around this, the modelChange listener isn't bound until after all of the enactors are ready.
GPII-147, GPII-160: fixed ToC links

Now only looking for headers that are in the simplified content. This is done with a complex selector passed to the ToC. I had attempted to use the ToC's refresh capabilities to rerender the ToC when simplified, but was unable to get the timing right.
Merge branch 'master' into GPII-147
Merge branch 'master' into GPII-147
Merge remote-tracking branch 'jobara/GPII-147'

* jobara/GPII-147:
  GPII-147, GPII-160: fixed ToC links
  GPII-147: don't convert model on init