fixing windows handling of eastern standard time

date_windows.go

@@ -0,0 +1,17 @@
+// +build windows
+
+package chart
+
+import "time"
+
+// Eastern returns the eastern timezone.
+func (d date) Eastern() *time.Location {
+	if _eastern == nil {
+		_easternLock.Lock()
+		defer _easternLock.Unlock()
+		if _eastern == nil {
+			_eastern, _ = time.LoadLocation("Eastern Standard Time")
+		}
+	}
+	return _eastern
+}