soft-limit.js is dependent on drupal.js

soft-limit.js is dependent on the drupal.js library because it uses Drupal.behaviors. This is one of those things that is easy to miss if you're looking at the site while logged in as an admin or if you have other modules enabled with JS that is dependent on it. I've done it before in one of my modules.

I found the problem today because I'm working on a site with a really stripped-down theme and not many other modules enabled. You can reproduce the issue by looking a soft-limited facet block on a site without many modules enabled while anon with Bartik enabled.

I've attached a patch. Thanks!