First run page triggering

src/plugin/PluginUtil.h

 #pragma once
 #include <string>
 
 class BString
 {
 public:
   BString(const std::wstring& value);
   ~BString();
   operator BSTR();
 private:
   BSTR value;
   BString(const BString&);
   BString& operator=(const BString&);
 };
 
+std::wstring HtmlFolderPath();
 std::wstring UserSettingsFileUrl();
+std::wstring FirstRunPageFileUrl();
 std::wstring FileUrl(const std::wstring& url);