small PluginManager UI updates

- click category heading on Available tab to show/hide plugins in that category
- add initial sort for plugins on Installed tab
- no mouseover bgcolor for Advanced tab


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@31819 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/PluginManager.java

@@ -233,6 +233,7 @@ public abstract class PluginManager extends AbstractModelObject {
                                         stop(); // disable all plugins since classloading from them can lead to StackOverflow
                                         throw e;    // let Hudson fail
                                     }
+                                    Collections.sort(plugins);
                                 }
                             });