Fix page_available event not being called due to wrong paths.

When files from a nested archive were extracted, archive_extractor
used the wrong temporary directory to create the absolute path of
the extracted image. This prevented main.page_available from firing
further down the line. This way, the user would have to click
before any image would be shown.

git-svn-id: https://mcomix.svn.sourceforge.net/svnroot/mcomix@795 6cf541bf-b722-4a7c-9fc0-fb1e75421f59
GUI prototype to edit "Open with..." commands.

No functionality has been implemented yet.

git-svn-id: https://mcomix.svn.sourceforge.net/svnroot/mcomix@796 6cf541bf-b722-4a7c-9fc0-fb1e75421f59