Better time formatting, tweaking and more fixes

The IRC and Chat tab use luas time formatting now
(http://gmodwiki.net/Lua/Libraries/os/date).
Changed some parts of function descriptions using 4 spaces instead of a
tab.
Tab panels have a border now.
ProcessText of the Chat tab can process tables recursively now.
Improved IRC message parsing performance.
Fixed channel tabs reopening to show the disconnect message when closing
a channel.
Text in text entrys (IRC and Chat) gets deleted when closing the chat
now.