fix MainWindow size adjustment offset(h+2), abstract chatroom JTextPane to
another class ChatroomPanel
JtvIRCBot: handle jtv PRIVMSG CLEARCHAT (user) message, display event as a
System log
rename JtvIRCBot Listeners, depart some methods of Msg Listener into a new
Event Listener interface (IRCEventListener)
add Chatroom border option
Main window is now resizable (by dragging the window border)
update README, fix MainWindow connect/disconnect switch bug, update a user
get banned message