Massive JavaScript cleanup

- Use JSX for templates
- Docblock/comment everything
- Mostly passes ESLint (still some work to do)
- Lots of renaming, refactoring, etc.

CSS hasn't been updated yet.

js/lib/utils/humanTime.js

@@ -0,0 +1,28 @@
+/**
+ * The `humanTime` utility converts a date to a localized, human-readable time-
+ * ago string.
+ *
+ * @param {Date} time
+ * @return {String}
+ */
+export default function humanTime(time) {
+  const m = moment(time);
+
+  const day = 864e5;
+  const diff = m.diff(moment());
+  let ago = null;
+
+  // If this date was more than a month ago, we'll show the name of the month
+  // in the string. If it wasn't this year, we'll show the year as well.
+  if (diff < -30 * day) {
+    if (m.year() === moment().year()) {
+      ago = m.format('D MMM');
+    } else {
+      ago = m.format('MMM \'YY');
+    }
+  } else {
+    ago = m.fromNow();
+  }
+
+  return ago;
+};