notifications 6.x-1.0-beta1

Lots of bug fixes and some new features:
- Fixed untranslatable strings, not wrappend in t(), #274049
- Using node_access instead of user switching, by moshe, #284444
- Better description for autosubscribe option, by wallan, #247616
- Fixed: Old node data sent upon node update, david_g, #278530
- Fixed: several limit cases with cron processing, #276370, #270324
- Updated unit tests for latest change in notifications_get_link() return values.
- Ported latest bug fixes from 5.x version.
- Fixed incomplete upgrade of notifications_tags, by fab65, #269725
- Fixed bug with notifications_ui block, incomplete upgrade of form functions, #256775
- Fixed: Notifications queued when send interval is 'Never', by Scott Reinolds, #268662
- Added: PHP4 compatibility function, by phonydream2, #261902
- Added event/hook support for not saving/queueing some event types, #255402
- Removed "Duplicated subscription found and updated message", #260436
- Theme username for notifications by author list, by jaydub, #253989
- Fixed Wrong redirection and user message not showing up after subscribing, #251979
- Reworked subscribe/unsubscribe pages, added confirmation for unsubscribe.
- Ported critical bug fix from Beta3, http://drupal.org/node/253401
- Upgraded mail2web module for Drupal 6
- Ported latest features from 5.x branch
- Main Drupal 6 upgrade