Upgrade devDependencies

Upgrades to latest versions of testing libraries and Redis library.

Also addresses security alert in Minimist package, used indirectly by Mocha.

Upgrade devDependencies

Address security alert in Handlebars which is used by the testing library.

Add support for HSCAN, SSCAN, and ZSCAN

Each of the four scan methods Redis provides are now accessible via this library. Previously only the core SCAN method was supported. Now you can scan through hashes, sets, and sorted sets.

It's also now possible to specify the COUNT option for controlling how much work Redis should perform in each iteration of the scan.

Small patch

Trivial improvements and dev dependency updates since initial launch.