quiet some warnings which appear on vs2015.

quieted warnings include shadowed variable names and integer extensions.

Externals/wxWidgets3/include/wx/app.h

@@ -541,7 +541,7 @@ public:
         // very first initialization function
         //
         // Override: very rarely
-    virtual bool Initialize(int& argc, wxChar **argv);
+    virtual bool Initialize(int& _argc, wxChar **_argv);
 
         // a platform-dependent version of OnInit(): the code here is likely to
         // depend on the toolkit. default version does nothing.

Externals/wxWidgets3/include/wx/msw/app.h

@@ -29,7 +29,7 @@ public:
     virtual ~wxApp();
 
     // override base class (pure) virtuals
-    virtual bool Initialize(int& argc, wxChar **argv);
+    virtual bool Initialize(int& _argc, wxChar **_argv);
     virtual void CleanUp();
 
     virtual void WakeUpIdle();