Add semver matching to package.json

NPM modules can quickly become dependency hell with no version constraints.  When you install a version with `npm install --save blah`, it will also cache a semantic version match in package.json.  This looks like ^x.y.z.  If the module is compliant with semantic versioning, future npm installs and updates will pull in the latest patch release (x.y.*) without breaking code compatibility.
Merge pull request #1 from calzoneman/master

Add semver matching to package.json