Updating package.json dependencies

Adding dependencies to package.json:
 - handlebars (moved from devDependencies since used in helpers/engines)
 - lodash
 - js-yaml
 - marked
 - highlight.js

These are all used in library modules that the assemble
task uses so they should be included for distribution (npm install)
Merge pull request #69 from doowb/master

Adding dependencies to package.json file.