DLL与模板
http://msdn.microsoft.com/en-us/library/twa2aw10.aspx
http://www.codesynthesis.com/~boris/blog/2010/01/18/dll-export-cxx-templates/
模板的前向声明和友元
http://msdn.microsoft.com/en-us/library/f1b2td24.aspx