[FEATURE] Get heroku run angular2

[ortichon]

1. get heroku to install node_modules in public folder.
   add the following script to main package.json scripts:

   "heroku-postbuild": "npm --prefix ./server/public install"

2. use angular-cli to create /dist folder
3. add express configuration to serve /dist folder when in distribution
4. add heroku env variable that states we are in dist

this article is gonna help

angular-cli docs

heroku customizing the build process