Updating restify and request

Updated **request@2.40.0** and **restify@2.8.2**.

Added an npm-shrinkwrap.json file and a few helpers:
- `npm run outdated`: lists outdated modules to console (or Travis log).
- `npm run shrinkwrap`: calls `npm shrinkwrap` and then calls `grunt validate-shrinkwrap`. This currently excludes `devDependencies` but it's an easy tweak if we decide to pin the version numbers instead of using semver range operators or `x`.
- `grunt validate-shrinkwrap`: validates the npm-shrinkwrap.json file against nodesecurity.io database.

Fixes #56