0.9.4claws19

0.9.4claws19

* src/procmsg.c
* src/common/utils.h
        add possibility to check all nodes with the same subject for
        subject threading, not only the oldest node. Should not break
        threads anymore if the oldest node is thread_by_subject_max_age
        days older then parent, because it can now find a child of
        oldest node as new parent.