Check esm_class delivery report flags (with config to disable if necessary) to avoid DRs escaping detection.
Relax DR regex by making various fields optional.
Merge branch 'develop' into feature/issue-872-use-smpp-esm-class-to-detect-dr
Non-capturing groups are (?:...), not (:?...).
Mention deferred return values in docstrings.
Merge branch 'feature/issue-872-use-smpp-esm-class-to-detect-dr' into develop