Merge branch 'subscription'

conf/dokuwiki.php

inc/actions.php

inc/common.php

inc/confutils.php

inc/form.php

inc/lang/de/lang.php

inc/lang/en/lang.php

inc/lang/en/subscr_digest.txt

inc/lang/en/subscr_form.txt

inc/lang/en/subscr_list.txt

inc/lang/en/subscr_single.txt

inc/pageutils.php

inc/subscription.php

inc/template.php

lib/exe/indexer.php

lib/exe/js.php

lib/plugins/config/lang/en/lang.php

lib/plugins/config/settings/config.metadata.php

lib/scripts/subscriptions.js

lib/tpl/default/_subscription.css