Reload features on save

My primary concern for this PR was getting it so when I press save on one of the tabs that the view on the main screen updates correctly. Previously, any changes that were saved did not show up until the page was refreshed.
Now, you are taken to the home page and the view is updated (turns a newly activated feature to green without reloading the browser, as an example.) Also, when a tab is saved, we change the url to be the main app's url so that if the browser is refreshed, the user sees the same view as before the browser refresh. Running `rake` passes.

Caveats:
I am not super familiar with Spine conventions, so any suggestions/improvements are welcome. I was not able to get the main page view to update when a percentage slider changed, although this also does not appear to be correct on page refresh either, so I think this is a separate task.