Package dependency update. Updated jade to pug.

[justinhartman]

I was getting dependency deprecation warnings when building. Specifically:

npm WARN deprecated jade@1.11.0: Jade has been renamed to pug, please install the latest version of pug instead of jade
npm WARN deprecated connect@2.17.3: connect 2.x series is deprecated
npm WARN deprecated transformers@2.1.0: Deprecated, use jstransformer
npm WARN deprecated minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN deprecated minimatch@0.2.14: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN deprecated graceful-fs@1.2.3: graceful-fs v3.0.0 and before will fail on node releases >= v7.0. Please update to graceful-fs@^4.0.0 as soon as possible. Use 'npm ls graceful-fs' to find it in the tree.

Updating Jade to Pug solves this.