@Akbeard in SS2.0 you can upload a library like moment js to the file cabinet say:

SuiteScripts/repo/custommodules/vendors/moment.min.js

Then within the script you want to include it on you can add it to the modules you require:

define([ 'SuiteScripts/repo/custommodules/vendors/moment.min.js'],
  function(moment)
 {
  //.....
})