Fix bug: Footprint add 3D shape recognizes only files with lower case ext on Windows

Fixes: lp:1659027
https://bugs.launchpad.net/kicad/+bug/1659027

3d-viewer/3d_cache/3d_cache.cpp

@@ -390,7 +390,11 @@ bool S3D_CACHE::getSHA1( const wxString& aFileName, unsigned char* aSHA1Sum )
         return false;
     }
 
+    #ifdef WIN32
+    FILE* fp = _wfopen( aFileName.wc_str(), L"rb" );
+    #else
     FILE* fp = fopen( aFileName.ToUTF8(), "rb" );
+    #endif
 
     if( NULL == fp )
         return false;