list: cleanup, include offset in DateAttempt

included UTC offset in minutes in DateAttempt, will be used shortly.
Also moved this stuff (ParsedDate, DateAttempt) to the common d.ts, and
the method for parsing from a string (now parseDateString) to common.
Also pre-emptively load the user cache when the admin page loads.

ts/modules/common.ts

@@ -1,4 +1,5 @@
 declare var window: GlobalWindow;
+import dateParser from "any-date-parser";
 
 export function toDateString(date: Date): string {
     const locale = window.language || (window as any).navigator.userLanguage || window.navigator.language;
@@ -21,6 +22,20 @@ export function toDateString(date: Date): string {
     return date.toLocaleDateString(locale, args1) + " " + date.toLocaleString(locale, args2);
 }
 
+export const parseDateString = (value: string): ParsedDate => {
+    let out: ParsedDate = {
+        text: value,
+        // Used just to tell use what fields the user passed.
+        attempt: dateParser.attempt(value),
+        // note Date.fromString is also provided by dateParser.
+        date: (Date as any).fromString(value) as Date
+    };
+    out.attempt.offsetMinutesFromUTC = out.date.getTimezoneOffset();
+    // Month in Date objects is 0-based, so make our parsed date that way too
+    if ("month" in out.attempt) out.attempt.month -= 1;
+    return out;
+}
+
 export const _get = (url: string, data: Object, onreadystatechange: (req: XMLHttpRequest) => void, noConnectionError: boolean = false): void => {
     let req = new XMLHttpRequest();
     if (window.pages) { url = window.pages.Base + url; }