Varnish together with Expire and Domain Access modules

This issue is related to this one #1323418: Support for Expire module option expire_include_base_url=1

When using Expire and Domain Access modules together with Varnish and have set expire_include_base_url to True in Expire settings, the paths sent to varnish_expire_cache function are the full URLs (ex. 'http://www.example.com/', 'http://www.example.it/page','http://www.example.se/page') which results in strange commands sent to varnish looking like:
ban req.http.host ~ "www.example.com" && req.url ~ "/http://www.example.com/some-page$|^/http://www.example.it/some-page$|^/http://www.example.es/some-page"

So the following patch handles several problems:

• fixes varnish_expire_cache function to sent the right commands to Varnish not the ones shown above.
• updates varnish_purge_all_pages so when a node is saved the cache is deleted not only on the current domain but on all aliases it may have
• Currently when Clear All Caches button is clicked in Configuration->Performance it clears Varnish cache only on current domain. So a checkbox is added to choose wheather to delete on current(and its aliases) or an all exisiting domains.