Updated German translation and increased FormUpdates dialog to accomodate long URLs

Updated German translation and increased FormUpdates dialog to accomodate long URLs when a new Git Extensions package is announced.

![gitextensionupdates_tooshortdialog](https://f.cloud.github.com/assets/3082683/2021449/6c279430-883f-11e3-94f7-ca137ff48046.jpg)