Add option to hide "user has joined/left conversation" messages

[flynd]

When using MSN, the notice "user has joined the conversation." and "user has left the conversation." is displayed in the chat window, often several times during a conversation. I think there is an idle timeout of one minute triggering a "left" notice. A "joined" notice is then printed together with the next chat-messege sent or recieved.
As these "left" and "joined" notices has no relation to typing-notification or whether the other user has closed his/her chat window they are just annoying.
I suggest having a checkbox to control if these notices should be displayed or not. (Currently I've comment out a few lines from the gui-code to get rid of them.)

And by the way, the GUI does not seem to have an option to set the colour of these notices. They are always green.

[flynd]

I now also noticed that the left/joined notices uses the protocol id of the contact. This should be changed to use the alias instead.

[flynd]

Here is a patch to allow changing the color of the notices.

[erijo]

The color patch was committed in r4736.

[flynd]

Patch to display alias instead of protocol id in join/left notices.

[erijo]

licq-4756_notice_use_alias.patch committed in r4757.

[flynd]

Adds an option to hide the join/left notices.

[erijo]

Slightly modified.

[erijo]

attachment:licq-4791-optional_notices_v2.patch committed in r4792.