Translation exports packaged as TGZ files now run fully in memory instead of using temporary files, reducing cleanup issues and making the process more reliable. The completion dialog was also refreshed to remove outdated documentation and Launchpad links.

* Little reason to implicate the filesystem in that mess, and the tempdir was not cleaned up. Do the entire thing in-memory.
* Update end-of-process dialog, it had way outdated links (6.1 & launchpad).