Added wxInfoBar::Dismiss().

Add a method to conveniently hide the info bar and update the parent layout.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62284 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/infobar.h

@@ -41,6 +41,8 @@ public:
     virtual void ShowMessage(const wxString& msg,
                              int flags = wxICON_INFORMATION);
 
+    virtual void Dismiss();
+
     virtual void AddButton(wxWindowID btnid,
                            const wxString& label = wxString());