Escape double quotes in headlines

* org-taskjuggler.el (org-taskjuggler-components): Escape quotes in
headlines.

Taskjuggler will barf if the task names (which are double quoted
strings) contain double quotes.

lisp/org-taskjuggler.el

@@ -354,7 +354,9 @@ information, all the properties, etc."
   (let* ((props (org-entry-properties))
 	 (components (org-heading-components))
 	 (level (nth 1 components))
-	 (headline (nth 4 components))
+	 (headline 
+	  (replace-regexp-in-string 
+	   "\"" "\\\"" (nth 4 components) t t)) ; quote double quotes in headlines
 	 (parent-ordered (org-taskjuggler-parent-is-ordered-p)))
     (push (cons "level" level) props)
     (push (cons "headline" headline) props)