Postfix enhancements
See commit log / commits.
Fixes #5606 (closed). Fixes #3769 (closed). Fixes #5532 (closed). Fixes #1251 (closed). Fixes #5472 (closed). Fixes #2065 (closed). Fixes #5667 (closed).
Adds a couple options falling under #3624 (closed).
Might fix, or at least improves #5627 (closed).