Provide wxApp::StoreCurrentException() implementation for C++11.

When using C++11 we can provide implementations of wxApp::StoreCurrentException()
and RethrowStoredException() ourselves and thus make catching exceptions outside
of the event loop work by default.

Do this and update the documentation and the sample to reflect it.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77470 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/app.h

@@ -306,16 +306,25 @@ public:
 
     // This function can be overridden to store the current exception, in view
     // of rethrowing it later when RethrowStoredException() is called. If the
-    // exception was stored, return true. The default implementation returns
-    // false, indicating that the exception wasn't stored and that the program
-    // should be simply aborted.
+    // exception was stored, return true. If the exception can't be stored,
+    // i.e. if this function returns false, the program will abort after
+    // calling OnUnhandledException().
+    //
+    // The default implementation of this function when using C++98 compiler
+    // just returns false, as there is no generic way to store an arbitrary
+    // exception in C++98 and each application must do it on its own for the
+    // exceptions it uses in its overridden version. When using C++11, the
+    // default implementation uses std::current_exception() and returns true,
+    // so it's normally not necessary to override this method when using C++11.
     virtual bool StoreCurrentException();
 
     // If StoreCurrentException() is overridden, this function should be
     // overridden as well to rethrow the exceptions stored by it when the
-    // control gets back to our code, i.e. when it's safe to do it. The default
-    // version does nothing.
-    virtual void RethrowStoredException() { }
+    // control gets back to our code, i.e. when it's safe to do it.
+    //
+    // The default version does nothing when using C++98 and uses
+    // std::rethrow_exception() in C++11.
+    virtual void RethrowStoredException();
 #endif // wxUSE_EXCEPTIONS