comment_notify 5.x-2.2

This is the third official release for 5.x-2.x branch and provides several new features and bug fixes. Some of the strings have changed slightly so I would appreciate translators providing new translations.

Changes since DRUPAL-5--2-1:

• bug #311253 by greggles: Unsupported Operands when editing or replying to a comment
• bug #308585 by greggles: partial fix for pgsql compliance
• bug #308585 by ulhume: PostgreSQL compliance using condition on uid rather than '' for NULL
• bug #317638 by Junyor: Thinko in the Pgsql case - should be creating table comment_notify, not re-creating the comments table
• bug #317638 by Junyor: Thinko in the Pgsql case - should be creating table comment_notify, not re-creating the comments table round 2
• oops - syntax error
• bug #294095 by greggles: notify_hash could just use drupal_get_token
• feature #280502 by greggles: optionally only send notifications for replies to the specific comment.
• feature #221196 by greggles: allow notifications for node owner
• feature #280502 followup by greggles: let the admin choose which modes are enabled in case, for example, they don't use threaded comments
• some whitespace cleanup already done in 6
• proper capitalization - sorry translators
• improved docs