mu4e: implement mu4e-compose-complete-only-after

We weren't supporting that yet after moving to the new command-parser;
let's do so now.

We now pass the time_t as a string, since the parser does not support
floats (and emacs doesn't generally support big ints).

mu4e/mu4e-proc.el

@@ -483,7 +483,7 @@ AFTER is non-nil, get only contacts seen AFTER (the time_t
 value)."
   (mu4e~call-mu `(contacts
                    :personal ,personal
-                   ;; :after  ,(or after nil)
+                   :after  ,(or after nil)
                    :tstamp ,(or tstamp nil))))
 
 (defun mu4e~proc-view (docid-or-msgid &optional images decrypt)

mu4e/mu4e-utils.el

@@ -780,11 +780,8 @@ nothing."
     (setq mu4e-contacts-func 'mu4e~update-contacts)
     (mu4e~proc-contacts
       mu4e-compose-complete-only-personal
-      (when mu4e-compose-complete-only-after
+      mu4e-compose-complete-only-after
-	      (float-time
+	    mu4e~contacts-tstamp)))
-	        (apply 'encode-time
-	          (mu4e-parse-time-string mu4e-compose-complete-only-after))))
-      mu4e~contacts-tstamp)))
 
 (defun mu4e~pong-handler (props func)
   "Handle 'pong' responses from the mu server."

mu4e/mu4e-vars.el

@@ -370,9 +370,13 @@ addresses)."
 
 (defcustom mu4e-compose-complete-only-after "2014-01-01"
   "Consider only contacts last seen after this date.
-Date must be a string, in a format parseable by
+
-`org-parse-time-string'. This excludes really old contacts.
+Date must be a string of the form YYY-MM-DD.
-Set to nil to not have any time-based restriction."
+
+This is useful for limiting a potentially enormous set of
+contacts for auto-completion to just those that are present in
+the e-mail corpus in recent timses. Set to nil to not have any
+time-based restriction."
   :type 'string
   :group 'mu4e-compose)