Typo in link to 'implementing a Hello World http server'. (#110)

* Typo in link to 'implementing a Hello World http server'.

* Changing username

Author: vprusso

dart_io_mini_samples/README.md

@@ -1,4 +1,3 @@
-
 * [Introduction](example/introduction.md)
 
 ## Files, directories, and symlinks
@@ -36,7 +35,7 @@
 
 ## HTTP server
 
-* [Implementing a 'Hello world' HTTP server](example/http_server/implementing_a_hello_world_http_server.dart)
+* [Implementing a 'Hello world' HTTP server](example/http_server/implementing_a_Hello_World_http_server.dart)
 * [Routing requests based on URL patterns](example/http_server/routing_requests_based_on_url_patterns.dart)
 
 ## Sockets