Load timezones asynchronously.

This prevents the Chicago example from showing up blank.  The
alternative is to define a callback, but that's messier.

examples/axes-time-zones/index.html

@@ -15,7 +15,7 @@
 
 		timezoneJS.timezone.zoneFileBasePath = "tz";
 		timezoneJS.timezone.defaultZoneFile = [];
-		timezoneJS.timezone.init();
+		timezoneJS.timezone.init({async: false});
 
 		var d = [
 			[Date.UTC(2011, 2, 12, 14, 0, 0), 28],