Updater v2.1

```
* Change version from 2.0 to 2.1
* Add userAgent to class header
* Add updaterConfigFileName to class header
* Add getRemoteName()
* Add getRemoteVersion()
* Store downloaded files in own workdir inside server update directory
* cleanup working directory before downloading file
* Fixes "java.util.zip.ZipException: error in opening zip file"
* Set ZipFile to ZipFile.OPEN_READ
* UpdateRunnable will now throw an exception if any error occurred
* Adds Exceptions to class
```

As not all changes are probably fully suiteable for general use as you mentioned on the forums (e.g. workdir) I still would like to show you how i fixed the ZipException.