Explicitly requires additional password_strength dependency

[soundasleep]

Hi, I've just tried to install this into an existing project (using npm) and by default, it cannot be compiled:

$ npm install --save jquery-strength
$ # add reference to jquery-strength in existing JS using `require('jquery-strength')`
$ gulp build

Error: Cannot find module 'password_strength' from 'C:\...\node_modules\jquery-strength\dist'
    at C:\...\node_modules\browser-resolve\node_modules\resolve\lib\async.js:1:18

I had to npm install --save password_strength separately for this package to work.

It appears there might be some sort of invalid dependency reference somewhere. package-lock.json lists "@fnando/password_strength" as a dependency, there are no password_strength dependencies loaded.