Revert "Update Broccoli build definition for clarity, regen npm-shrinkwrap.json"

This reverts commit 89d77e44536647f2c3f7c464aaf4d53d8b189bbb.
Revert "Revert "Update Broccoli build definition for clarity, regen npm-shrinkwrap.json""

This reverts commit 8d68830b0e9e2411e025af33a8aa873ec6905a54.
Downgrade Express to 3.5, because 3.6 is broken