<li>The API endpoint is <code>GET [project_url]/api/timestamp/:date_string?</code></li>
<li>A date string is valid if can be successfully parsed by <code>new Date(date_string)</code>.<br>
Note that the unix timestamp needs to be an <strong>integer</strong> (not a string) specifying <strong>milliseconds</strong>.<br>
In our test we will use date strings compliant with ISO-8601 (e.g. <code>"2016-11-20"</code>) because this will ensure an UTC timestamp.</li>
<li>If the date string is <strong>empty</strong> it should be equivalent to trigger <code>new Date()</code>, i.e. the service uses the current timestamp.</li>
<li>If the date string is <strong>valid</strong> the api returns a JSON having the structure<br><code>{"unix": <date.getTime()>, "utc" : <date.toUTCString()> }</code><br>
e.g. <code>{"unix": 1479663089000 ,"utc": "Sun, 20 Nov 2016 17:31:29 GMT"}</code></li>
<li>If the date string is <strong>invalid</strong> the api returns a JSON having the structure <br>
