Make roofcam update every 5 minutes and have no html default

I made it so that the javascript will default to north camera on first upload, that way we don't need to add a default to the html.

I also made new images update every 5 minutes by doing t=DDHH(M//5). example: 02/27/2020 1:47PM would be t=27139.

content/js/meteorogram/plot/update.js

@@ -47,15 +47,19 @@ function updateHeader(dataCache, unitCount, layoutUpdates) {
 }
 
 
-
 function changeCamera() {
     var directions = {'north': 'east', 'east': 'south', 'south': 'west', 'west': 'north',};
     // Gets witch direction the current camera is showing.
     var newDirection = directions[document.getElementById('roofCam').src.split('/')[7]];
+    // Default to North on first load.
+    newDirection = newDirection ? newDirection : 'north';
     // Makes image update. Image updates every (about) 2 minutes and 15 seconds.
     document.getElementById('roofCam').alt = document.getElementById('dirText').innerHTML = newDirection;
-    document.getElementById('roofCam').src = 'http://metobs.ssec.wisc.edu/pub/cache/aoss/cameras/' + newDirection +
-                                             '/latest_orig.jpg?t=' + new Date().getTime();
+    var date = new Date();
+    // Update image every 5 minutes and let the final value be in seconds since epoch.
+    var formatted_date = Math.floor(date.getTime() / 1000 / 300) * 300;
+    document.getElementById('roofCam').src = METOBS_API_URL + '/pub/cache/aoss/cameras/' + newDirection +
+                                             '/latest_medium.jpg?t=' + formatted_date;
 }