Remove the object.observe polyfill and code which references it because it's no longer used
The unit details breakout was the last part of the app which was using the basic unit object format for the databdinding. This converts that to use a unit model by using revive() and free() on the lazyModelList
Merge pull request #450 from hatched/update-observe-polyfill

Remove the object.observe polyfill and revive unit objects to models where needed.

This branch removes the Object.observe polyfill and converts everywhere that still used the unit object in it's raw format to use `revived` unit models.