The current Travis script will only print offending files, but won’t fail the build. Added `--set-exit-if-changed` to fix that.
Also, simplified the call from using `grep` and `xargs` to simple `flutter format .`, which recurses directories.
Lastly, fixed offending files that needed `dartfmt`. (But not in the directories that aren’t covered by `travis_script.sh`.
I used `flutter create` anew, so the project structure now has additional 2 `AndroidManifest.xml` files. Everything else stayed the same, so from git’s perspective, it’s just moved files.
Adds sample app that mimics the beloved starter app, but with ScopedModel for state management.
Contains a smoke test and is set up to run it in travis_script.sh.
