issue #586 fixed the bug with incorrect timezones

The Timezone dropdown before (listing different timezones multiple times):
![screenshot](https://cloud.githubusercontent.com/assets/497645/2623052/40e74f78-bcd7-11e3-9ce0-6518f154ca81.png)
The Timezone dropdown with the patch (listing each timezone only once, and offsets with time fraction not rounded up):
![screen2](https://cloud.githubusercontent.com/assets/497645/2623058/714e6692-bcd7-11e3-87aa-6bcade115ae9.png)