Add warning messages when sending emoticons to a client which doesn't support them

[valerio]

When you chat with someone using a very old or reduced MSN client, like Windows Messenger (MSN5.0) or Meebo, KMess can easily read the contact's capabilities and/or version and notify you with an in-chat warning message that the contact's client is not capable of receiving emoticons/winks/nudges or whatever. This would avoid some annoyances.