mu4e: updates for core changes

Deal with (name . email) --> (:name "boo" :email "boo@example.com")
Add support for the new "changed" field.

mu4e/mu4e-helpers.el

@@ -504,6 +504,10 @@ in an external program."
 		 (lambda () (ignore-errors (delete-file tmpfile))))
     tmpfile))
 
+(defsubst mu4e-is-mode-or-derived-p (mode)
+  "Is the current mode equal to MODE or derived from it?"
+  (or (eq major-mode 'mode) (derived-mode-p mode)))
+
 (defun mu4e-display-manual ()
   "Display the mu4e manual page for the current mode.
 Or go to the top level if there is none."