Resurrection of the calculator app that was pulled from gaia.
If you plan to create, update, or destroy any files, please make sure to update the zip.
cd app zip application.zip newfile.whatever # add a new file into the zip zip -f applicaton.zip # Rezip modified contents aka freshen zip -d application.zip garbage.whatever # remove a file from the zip
Note: updating the zip is unnecessary if you're developing with the Firefox OS Simulator (Recommended). With the simulator, you can install as a packaged app by clicking Add Directory, then browsing to the manifest.webapp.