Add flag for "user limited time range", and wrap-band interval.

src/specks.h

@@ -237,6 +237,9 @@ struct stuff {
   struct specklist *scrap; /* stuff to be deleted when it's safe */
   int nghosts;		/* keep recent ghost snapshots of dynamic data */
 
+  int usertrange;
+  double usertwrap;
+
   /* async command streams */
 #define MAX_ASYNC 8
   FILE *asyncmd[MAX_ASYNC];