Simplify example instructions and fix broken examples

Also convert to AsciiDoc while we're at it.

examples/error_hook/README.asciidoc

@@ -0,0 +1,47 @@
+= Error hook example
+
+To try this example, you need GNU `make` and `git` in your PATH.
+
+To build and run the example, use the following command:
+
+[source,bash]
+$ make run
+
+Then point your browser to http://localhost:8080
+
+== Example output
+
+Not found:
+
+[source,bash]
+----
+$ curl -i http://localhost:8080
+HTTP/1.1 404 Not Found
+connection: keep-alive
+server: Cowboy
+date: Wed, 27 Feb 2013 23:32:55 GMT
+content-length: 56
+
+404 Not Found: "/" is not the path you are looking for.
+----
+
+Bad request:
+
+[source,bash]
+----
+$ telnet localhost 8080
+Trying ::1...
+Connection failed: Connection refused
+Trying 127.0.0.1...
+Connected to localhost.
+Escape character is '^]'.
+bad
+HTTP/1.1 400 Bad Request
+connection: close
+server: Cowboy
+date: Sun, 08 Sep 2013 09:29:27 GMT
+content-length: 15
+
+HTTP Error 400
+Connection closed by foreign host.
+----