There's no way that it would make sense to mandatorily switch from "any digits" to "semver only" -- it would break existing users, and I'm sure it would just annoy an alternate segment of the population. Instead, we keep the default behaviour, and if you want to go semver-only or some such, you can define your own regex to do whatever you want. I also tidied up the test fixtures a bit, and completely rewrote the StaticCache test suite to be properly structured. You're welcome.
Modifies response headers for client and proxy caching of static files that minimizes http requests and improves overall load times for second time visitors. Signed-off-by: Ryan Tomayko <email@example.com>