 README -- "wwwroot/components/" directory description.

   Please put "xenroll.dll" file in this directory. This DLL file
   is used for Internet Explorer certificate enrollment in the 
   Windows environment.

   "xenroll.dll", the Active X component, is normally found in
   the Windows system folder (ex. c:\windows\system32). Windows XP
   or later has latest DLL version, but older Windows doesn't have
   it. Therefore, if you want to use the web certificate enrollment
   with the aica certificate server, you should put the latest 
   version of "xenroll.dll" for windows users.
   
   Currently, version 5.131.3659.0 of "xenroll.dll" is supported.
   this version has "127698E4-E730-4E5C-A2b1-21490A70C8A1" for its
   Active X class id.
