Add wheezy backports support

Signed-off-by: Markus Rekkenbeil <markus@bionix-it.de>
Use the geoDNS http.debian.net instead of the main debian ftp server

Signed-off-by: Markus Rekkenbeil <markus@bionix-it.de>
Update specs for #145
Merge pull request #151 from hunner/proxy_exec_spec

Update specs for #145
Merge pull request #149 from bionix/add_wheezy_backports

Add wheezy backports support
Merge pull request #150 from bionix/use_http_debian_net_as_geodns_redirector

Use the geoDNS http.debian.net instead of the main debian ftp server