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.

usercache.go

@@ -235,11 +235,12 @@ const (
 }*/
 
 type DateAttempt struct {
-	Year   *int `json:"year,omitempty"`
-	Month  *int `json:"month,omitempty"`
-	Day    *int `json:"day,omitempty"`
-	Hour   *int `json:"hour,omitempty"`
-	Minute *int `json:"minute,omitempty"`
+	Year                 *int `json:"year,omitempty"`
+	Month                *int `json:"month,omitempty"`
+	Day                  *int `json:"day,omitempty"`
+	Hour                 *int `json:"hour,omitempty"`
+	Minute               *int `json:"minute,omitempty"`
+	OffsetMinutesFromUTC *int `json:"offsetMinutesFromUTC,omitempty"`
 }
 
 // Compare roughly compares a time.Time to a DateAttempt.