title: Firebase hosting and deploying only new/changed/touched files
body: <p>I'm using Firebase Hosting for hosting a web app. I'm also hosting some small screencasts on the site, however every time I want to make a change to the app and deploy, I have to wait for the videos to be pushed.</p>
  
  <p>Is there a way to <em>selectively</em> push changes to Firebase? Also, why does Firebase not simply push new/changed/touched files? I assume because its not doing any revision control for hosted applications and therefore isn't tracking such things, but that just makes the selective push much more of a need.</p>