added wxTextOutputStream::Flush(): this is necessary with the stateful encodings, such as UTF-7

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@53890 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/txtstrm.h

@@ -127,6 +127,8 @@ public:
 
     wxTextOutputStream& PutChar(wxChar c);
 
+    void Flush();
+
     wxTextOutputStream& operator<<(const wxString& string);
     wxTextOutputStream& operator<<(char c);
 #if wxUSE_UNICODE && wxWCHAR_T_IS_REAL_TYPE