* mu4e: add note about deprecating org-mode editing to doc
* mu-flags: add MU_FLAG_LIST, clean-up code a bit
* mu-msg-file: set the MU_FLAG_LIST flag, if the message looks like an ML-message
* mu-mgs-store: support the MU_FLAG_LIST flag
* mu-str: fix a leak
* cosmetic
* document the new flag:list