Added credit.

readme.html

@@ -926,6 +926,9 @@ their skills.  Special thanks go out to:</p>
   <li>Arturo J. Pérez, for a bug fix for cursor tracking on Mac OS X 10.6 Snow
   Leopard</li>
 
+  <li>Riku Salminen, for the initial implementation of
+  <code>glfwShowWindow</code> and <code>glfwHideWindow</code></li>
+
   <li>Douglas C. Schmidt and Irfan Pyarali, for their excellent article
   <a href="http://www.cs.wustl.edu/~schmidt/win32-cv-1.html">Strategies for Implementing POSIX Condition Variables on Win32</a></li>