Added chat buffer, now memorizes chat

[AssassinTee]

Chat is memorized, until you send it. If you switch to another chat-mode, the buffer will be cleared

[Dune-jr]

It works but there is no way of deleting the whole line other than by pressing Escape, so not being able to do that without changing chat modes is a bit counter-inuititve and clunky. Maybe Escape should keep its behavior and mouse clicks should allow a "soft exit"? Also I don't think messages should survive changing servers.

[AssassinTee]

• Delete buffer when leaving server
• Use mouse1 instead of Escape for the saving buffer

wip

[AssassinTee]

You can now come out of the chat with mouse1 and mouse2 (hook and fire) and your text is buffered and not lost.
The buffer is cleared when disconnecting.