remove Acl documentation

Author: havvg

Resources/doc/acl.markdown

@@ -108,7 +108,6 @@ class HelloController extends Controller
 
 Now you can read more about:
 
-* [The ACL Implementation](acl.markdown);
 * [The Commands](commands.markdown);
 * [The Fixtures](fixtures.markdown);
 * [The PropelParamConverter](param_converter.markdown);