Roadmap for simple_subscription 7.x-2.x

To first DEV release
------
1) Store subscriptions in table 'simple_subscription_subscribers'
  -> fields : sid, uid, mail, status, created, hash, deleted
2) Add configuration page with simple_subscription options
3) Add subscribers list page with filters and bulk actions form (cf. user admin page)
4) CSV export of subscribers list
5) Subscription form on user account edit form (configurable)
6) Manage un-subscriptions with confirmation mail (configurable)
7) Expose 'simple_subscription_subscribers' to views
8) API to add, change, delete subscribers
9) subscription / un-subscription hooks
10) checks :
  - Anonymous subscription of a registered drupal user forbidden. (configurable)
  - ?
11) Permissions : manage all subscriptions, manage own subscription

Needs some thinking
------
1) Extra fields on subscription form (configurable)
2) confirmation mail on subscription via block (from anonymous user)
3) subscription validation by admin (configurable)