update to r3056 from https://sourceforge.net/p/bacnet/code/3056/tree/trunk/bacnet-stack/ add ipv6 and schedule support

include/indtext.h

@@ -29,8 +29,8 @@
 #include <string.h>
 
 /* index and text pairs */
-typedef struct {
-    unsigned index;     /* index number that matches the text */
+const typedef struct {
+    const unsigned index;     /* index number that matches the text */
     const char *pString;        /* text pair - use NULL to end the list */
 } INDTEXT_DATA;