ALL: Massive 'const' cleanup

These changes facilitate more robust parameter type checking and helps
to identify unexpected coding errors.

Most simulators can now also be compiled with a C++ compiler without
warnings.

Additionally, these changes have also been configured to facilitate easier
backporting of simulator and device simulation modules to run under the
simh v3.9+ SCP framework.

Interdata/id16_dboot.c

@@ -305,7 +305,7 @@ static uint8 dboot_rom[] = {
 */
 
 struct dboot_id {
-    char        *name;
+    const char  *name;
     uint32      sw;
     uint32      cap;
     uint32      dtype;