Bugfix: Make sure to setActiveTab

Add an override for the new typed setInSlot (> GWTP 1.5.x) method and
make sure to call setActivTab on the corresponding tab.
The old untyped setInSlot will delegate to the new method.
This should fix #744

gwtp-core/gwtp-mvp-client/src/main/java/com/gwtplatform/mvp/client/TabContainerPresenter.java

@@ -19,6 +19,8 @@
 import com.google.gwt.event.shared.GwtEvent;
 import com.google.gwt.event.shared.GwtEvent.Type;
 import com.google.web.bindery.event.shared.EventBus;
+import com.gwtplatform.mvp.client.presenter.slots.IsSlot;
+import com.gwtplatform.mvp.client.presenter.slots.LegacySlotConvertor;
 import com.gwtplatform.mvp.client.proxy.Proxy;
 import com.gwtplatform.mvp.client.proxy.RevealContentHandler;
 import com.gwtplatform.mvp.client.proxy.TabContentProxy;
@@ -210,15 +212,20 @@ public Tab addTab(final TabContentProxy<?> tabProxy) {
 
     @Override
     public void setInSlot(Object slot, PresenterWidget<?> content) {
-        super.setInSlot(slot, content);
+        setInSlot(LegacySlotConvertor.convert(slot), content);
+    }
+
+    @Override
+    public <T extends PresenterWidget<?>> void setInSlot(IsSlot<T> slot, T child) {
+        super.setInSlot(slot, child);
 
         // TODO: Consider switching this to an event bus based mechanism where the
         // child presenter fires an event when it is revealed and the parent highlights the tab.
 
         // If we're setting a presenter attached to an actual slot, then highlight the tab
         if (slot == tabContentSlot) {
             try {
-                Presenter<?, ?> presenter = (Presenter<?, ?>) content;
+                Presenter<?, ?> presenter = (Presenter<?, ?>) child;
                 TabContentProxy<?> proxy = (TabContentProxy<?>) presenter.getProxy();
                 getView().setActiveTab(proxy.getTab());
             } catch (Exception e) {