Add helper utility for formatting dates before they're sent to the server.
Add import for json

Forgot to add this chunk previously.
Cut off the microsecond portion of date.

Backbone doesn't return microseconds when you save(), though our Add system does return the ISO format including microseconds. We don't need that much precision for our purposes, so let's just strip it out if it is there.
Tell Backbone to emulate JSON in its HTTP requests
Make "Activate" and "Deactivate" functionality work.

When deactivating an active asset, its end_date is set to NOW.
When activating an inactive asset, its start_date is set to NOW, and its end_date is set 10 years in the future.