extract CompositeView out of CollectionView

[mxriverlynn]

There's a high likelihood that this will end up being extended directly off CollectionView and just add a few more methods to make it work as a composite. I think the separation is necessary, though, to help avoid confusion and to help clean up the code. There's an issue in the code comments, here:

mxriverlynn@1ebbe70#commitcomment-1021855

that needs to be addressed when the extraction happens. I put in a quick hack in my own app to work around this but a good solution needs to be found. I don't think i wnat to change the way the HTML is attached. rather, I want to avoid re-rendering the ModelView when the collection is reset.

the hack i mention is to add these two lines to the top of the renderModel method in Marionette's CollectionView:

  if (this.modelViewRendered) { return; }
  this.modelViewRendered = true;

This will prevent the model view from being re-rendered when the reRender method is called. There are likely some side effects / drawbacks to this approach, and a better solution needs to be found.

[mxriverlynn]

in the dev branch, waiting for release