title: How to get week number since epoch? Like millis?
body: <p>I'm modeling a weekly reporting store in DynamoDb.</p>
  <p>I'm thinking the best way to identify the report-records is by their respective week number since 1970. Much like epoch milliseconds.</p>
  <p>Therefore:</p>
  <ol>
  <li>How to get to the current week number since 1970?</li>
  <li>How to get start and end dates given such week number?</li>
  </ol>
  <p>Considering all the possible edge cases I might not be aware of, like daylight savings and similar, I'm quite uncomfortable trying to solve this.</p>
  <hr />
  <p>Clarifications:</p>
  <ul>
  <li>Week starts Sunday night at midnight.</li>
  <li>In order to work out the exact time, the function 1. receives the desired UTC offset in minutes. (I'm open to suggestions here)</li>
  </ul>