Moved more files from FILENAME to FILENAME.txt ...

CREDITS → CREDITS.txt

@@ -98,5 +98,5 @@ Windows .rc file:
 Other stuff:
     Your name here! Patches go to icculus@icculus.org ...
 
-/* end of CREDITS ... */
+/* end of CREDITS.txt ... */
 

TODO → TODO.txt

@@ -58,5 +58,5 @@ Stuff:
 - Make mutexes recursive, so callbacks can call into the API.
 - Archivers need abstracted i/o to read from memory or files (archives in archives?)
 
-// end of TODO ...
+// end of TODO.txt ...
 

physfs.h

@@ -203,7 +203,7 @@
  * Please see the file LICENSE.txt in the source's root directory for licensing
  *  and redistribution rights.
  *
- * Please see the file CREDITS in the source's root directory for a more or
+ * Please see the file CREDITS.txt in the source's root directory for a more or
  *  less complete list of who's responsible for this.
  *
  *  \author Ryan C. Gordon.