Include filename in failure message. Add reminder to Readme.md.

Readme.md

@@ -39,6 +39,8 @@ How to build, run and embed?
 - If you want a compressed and fast (ie, with debug code removed) version, you
   need Closure Compiler. 
   Set the path to `compiler.jar` in the Makefile and run `make v86_all.js`.
+- ROM and disk images are loaded via AJAX, so if you want to try out `index.html`
+  locally, make sure to serve it from a local webserver.
 - For more details on how to customize the behaviour and interface, see [docs/adapters.md](docs/adapters.md).
 
 

src/browser/main.js

@@ -80,7 +80,7 @@ function dump_file(ab, name)
             {
                 if(http.status !== 200)
                 {
-                    log("Loading the image failed");
+                    log("Loading the image `" + filename + "` failed");
                 }
                 else if(http.response)
                 {