* Turn CacheBuster into a module
This class used no internal state, so repeatedly creating short-lived objects seems wasteful.
* Consistently use string interpolation and parenthesis
* Destructure arrays into meaningful names, formatting
* Fix request spec for internal classified listings controller
Interestingly this works when asserting directly on the module, but not on a double.
Asserting directly in the module seems sufficient for this test so the indirection
was removed.
* Turn CacheBuster into a module
This class used no internal state, so repeatedly creating short-lived objects seems wasteful.
* Fix specs after rebasing
