Push build artifacts from Travis to flysight-ci app

Travis-CI can build Flysight (#15), so I figured, why not have it upload the results somewhere? I played with `travis-artifacts` but eventually decided to roll a little web app of my own.

Builds get pushed to:
   https://flysight-ci.herokuapp.com/builds

You can look up a build by SHA1:
  https://flysight-ci.herokuapp.com/builds/bf093f052e766a67846c77989afd07d175a5ac58

It shows the size report and lets you download all the results. We can add other functions too, but I figured this was a good start.

The app runs on Heroku and fits in the free tier just fine. I added @crwper as a collaborator, so you can clone it or push to it or reconfigure it all you like. It authenticates uploads with a key, but I opted to include it unencrypted in `.travis.yml` so it'll uploads from cross-repository pull requests too. We can revisit that as needed.