message: script that installs addon now specifies --no-save  so that package.json is not updated.
  We don't want to accidentally add explicit dependencies of core on a particular addon and then
  check the package in that way.
diff: @@ -5,7 +5,7 @@ var exec = require('child_process').exec;
  let addonloader = require('./addonLoader');
  -let cmdLine = 'npm install ' + addonloader.computeAddonPackageName();
  +let cmdLine = 'npm install --no-save ' + addonloader.computeAddonPackageName();
  console.log(cmdLine + " ...");
  