WorldClock: Add some worldwide cities and update timezone

Add some cities info to xml.
When local is changed, the timezone in setting page should be
refreshed.

Change-Id: If13beeb3c92227f67819f016e4631913fc6daca7
WorldClock: Fix cities/time zone entries

* Remove duplicate entries
* Fix time zones for cities

Change-Id: I90a70b3059595f429eb5b12ad62aad953773d29c