wx: Silence -Woverloaded-virtual warnings with debug builds.

The Clone function seem unused, the AcceptsFocus and HasFocus
functions are marked as const and Show is renamed to ShowAddr
to not conflict with unrelated functions.

[187/196] Building CXX object src/wx/CMakeFiles/visualboyadvance-m.dir/viewsupt.cpp.o
In file included from ../src/wx/viewsupt.cpp:1:
../src/wx/viewsupt.h:197:10: warning: 'Viewers::MemView::Show' hides overloaded virtual function [-Woverloaded-virtual]
    void Show(uint32_t addr, bool force_update = false);
         ^
/usr/include/wx-3.0/wx/gtk/window.h:64:18: note: hidden overloaded virtual function 'wxWindow::Show' declared here: different number of parameters (1 vs 2)
    virtual bool Show( bool show = true );
                 ^
In file included from ../src/wx/viewsupt.cpp:1:
../src/wx/viewsupt.h:410:10: warning: 'Viewers::DispCheckBox::AcceptsFocus' hides overloaded virtual function [-Woverloaded-virtual]
    bool AcceptsFocus()
         ^
/usr/include/wx-3.0/wx/window.h:724:18: note: hidden overloaded virtual function 'wxWindowBase::AcceptsFocus' declared here: different qualifiers ('const' vs unqualified)
    virtual bool AcceptsFocus() const { return true; }
                 ^
In file included from ../src/wx/viewsupt.cpp:3:
In file included from ../src/wx/wxvbam.h:14:
In file included from ../src/wx/widgets/wx/joyedit.h:9:
../src/wx/widgets/wx/sdljoy.h:115:14: warning: 'wxSDLJoyEvent::Clone' hides overloaded virtual function [-Woverloaded-virtual]
    wxEvent* Clone();
             ^
/usr/include/wx-3.0/wx/event.h:1569:22: note: hidden overloaded virtual function 'wxCommandEvent::Clone' declared here: different qualifiers ('const' vs unqualified)
    virtual wxEvent *Clone() const { return new wxCommandEvent(*this); }
                     ^
In file included from ../src/wx/viewsupt.cpp:3:
../src/wx/wxvbam.h:286:10: warning: 'MainFrame::HasFocus' hides overloaded virtual function [-Woverloaded-virtual]
    bool HasFocus()
         ^
/usr/include/wx-3.0/wx/window.h:715:18: note: hidden overloaded virtual function 'wxWindowBase::HasFocus' declared here: different qualifiers ('const' vs unqualified)
    virtual bool HasFocus() const;
                 ^
4 warnings generated.

src/wx/viewers.cpp

@@ -679,7 +679,7 @@ public:
     }
     void Goto(uint32_t addr)
     {
-        mv->Show(addr, true);
+        mv->ShowAddr(addr, true);
     }
     void RefreshCmd(wxCommandEvent& ev)
     {

src/wx/viewsupt.cpp

@@ -725,7 +725,7 @@ void MemView::Resize(wxSizeEvent& ev)
         Refill();
 }
 
-void MemView::Show(uint32_t addr, bool force_update)
+void MemView::ShowAddr(uint32_t addr, bool force_update)
 {
     if (addr < topaddr || addr >= topaddr + (nlines - 1) * 16) {
         // align to nearest 16-byte block

src/wx/viewsupt.h

@@ -194,7 +194,7 @@ private:
 
 public:
     // make addr visible
-    void Show(uint32_t addr, bool force_update = false);
+    void ShowAddr(uint32_t addr, bool force_update = false);
 
     // current selection, or topaddr if none
     uint32_t GetAddr();
@@ -407,7 +407,7 @@ protected:
 // a display-only checkbox which does not look like it's disabled
 class DispCheckBox : public wxCheckBox {
 public:
-    bool AcceptsFocus()
+    bool AcceptsFocus() const
     {
         return false;
     }

src/wx/widgets/wx/sdljoy.h

@@ -111,8 +111,6 @@ public:
     {
         return prev_val;
     }
-    // required for PostEvent, apparently
-    wxEvent* Clone();
 
 protected:
     unsigned short joy;

src/wx/wxvbam.h

@@ -283,7 +283,7 @@ public:
     void set_global_accels();
 
     // 2.8 has no HasFocus(), and FindFocus() doesn't work right
-    bool HasFocus()
+    bool HasFocus() const
     {
         return focused;
     }