Fix issues in reporting netclasses.

1) make sure we get the default netclass when we want it
2) escape for HTML (particularly important for "<invalid>", but also
for reporting user rule names, netclass names, etc.)

common/string.cpp

@@ -338,7 +338,7 @@ std::string EscapedUTF8( wxString aString )
 }
 
 
-wxString EscapedHTML( const wxString& aString )
+wxString EscapeHTML( const wxString& aString )
 {
     wxString converted;