Update docs for v3.3
The current docs still refer to version 3.2.
- New: X-UNSET-FINGERPRINT
- Change description of X-SET-FINGERPRINT ("X-SET-FINGERPRINT will not anymore allow setting an empty fingerprint")
- Text change required for this? "Parse keywords up to the first line detected as mail content"
- Text change required for this? "Extend the pseudoheaders configuration option to support 'sig' and 'enc' as configurable and sortable fields."
- Add to description of X-UNSUBSCRIBE: "X-UNSUBSCRIBE will refuse to unsubscribe the last admin of a list. "