patch 7.4.1341

Problem:    It's difficult to add more arguments to ch_sendraw() and
            ch_sendexpr().
Solution:   Make the third option a dictionary.

src/structs.h

@@ -1373,11 +1373,12 @@ struct channel_S {
 };
 
 /*
- * Options for job commands.
+ * Options for job and channel commands.
  */
 typedef struct
 {
-    ch_mode_T	jo_mode;
+    ch_mode_T	jo_mode;	/* "mode" */
+    char_u	*jo_callback;	/* "callback", not allocated! */
 } jobopt_T;