Add missing headers that are in agi_pre.h but not the actual header, should fix the non-precompiled header build.

Originally committed to SVN as r3529.

aegisub/src/dialog_selection.h

@@ -48,6 +48,7 @@
 #include <wx/combobox.h>
 #include <wx/dialog.h>
 #include <wx/radiobox.h>
+#include <wx/radiobut.h>
 #include <wx/string.h>
 #include <wx/textctrl.h>
 #endif

aegisub/src/vfr.h

@@ -44,18 +44,18 @@
 
 ///////////
 // Headers
-#ifndef AGI_PRE
 
+#ifndef AGI_PRE
 #include <list>
 #include <vector>
 
 #include <wx/dynarray.h>
+#include <wx/string.h>
 #endif
 
 #include "include/aegisub/aegisub.h"
 
 
-
 /// DOCME
 enum ASS_FrameRateType {