Fix a memory deallocation error that was crashing q2dm.

Also fix a bunch of compile warnings by changing "char *" to "const char *".
diff --git a/emulator/qtools/read_addr.cpp b/emulator/qtools/read_addr.cpp
index 38fc62a..1c8c20f 100644
--- a/emulator/qtools/read_addr.cpp
+++ b/emulator/qtools/read_addr.cpp
@@ -20,7 +20,7 @@
 
     if (trace->ReadAddr(&time, &addr, &flags))
       break;
-    char *op = "ld";
+    const char *op = "ld";
     if (flags == 1)
         op = "st";
     printf("%lld 0x%08x %s\n", time, addr, op);