Change the existing client flags for control mode to apply for any

client, use the same mechanism for the read-only flag and add an
ignore-size flag.

refresh-client -F has become -f (-F stays for backwards compatibility)
and attach-session and switch-client now have -f flags also. A new
format "client_flags" lists the flags and is shown by list-clients by
default.

This separates the read-only flag from "ignore size" behaviour (new
ignore-size) flag - both behaviours are useful in different
circumstances.

attach -r and switchc -r remain and set or toggle both flags together.

cmd-list-clients.c

@@ -28,10 +28,10 @@
  * List all clients.
  */
 
-#define LIST_CLIENTS_TEMPLATE					\
-	"#{client_name}: #{session_name} "			\
-	"[#{client_width}x#{client_height} #{client_termname}]"	\
-	"#{?client_utf8, (utf8),} #{?client_readonly, (ro),}"
+#define LIST_CLIENTS_TEMPLATE						\
+	"#{client_name}: #{session_name} "				\
+	"[#{client_width}x#{client_height} #{client_termname}] "	\
+	"#{?client_flags,(,}#{client_flags}#{?client_flags,),}"
 
 static enum cmd_retval	cmd_list_clients_exec(struct cmd *, struct cmdq_item *);