Ember-cli upgrade broke everything

I had a running Ember program built using Ember-Cli 1.13.12 using Node 4.2.4. I tried to upgrade to Ember-Cli 2.3.0 running on Node 4.2.6. I followed the procedure outlined in: http://ift.tt/1ysP6WQ. After the upgrade, my program generated all sorts of errors. I spent an entire day trying to get the program to work but couldn't. So I decided to try reverting back to Ember-cli 1.13.12. I checked out the lastest working version of my program before the upgrade attempt using git. I did the following to revert back to Ember-cli 1.13.12:

  npm uninstall -g ember-cli
  npm cache clean
  bower cache clean
  npm install -g ember-cli@1.13.12

  rm -rf node_modules bower_components dist tmp
  npm install
  bower install

But the system still doesn't work. 'Ember Server' works as expected. But when I go to localhost:4200 in my browser, I get two errors:

 Uncaught Error: Assertion Failed: Ember Views require jQuery between 1.7 and 2.1
 Uncaught Error: Could not find module `ember` imported from `tw/app`

Can someone please help me figure out what's going on?