Adds 'You're now known as' for nick change.

This adds a more elaborate notification about nick change.

If, for instance, a nick-change was forced by the *bnc* and other users with extremely similar names exists in the channel, a user might not notice that his nick has been changed.

Previous:

	[12:09:51] 	 user is now known as apx`
	[12:09:54] 	 user2 is now known as `apx
	[12:09:58] 	 apx (<= local user) is now known as apx_
	[12:09:59] 	 user3 is now known as `apx`

Now:

	[12:09:51] 	 user is now known as apx`
	[12:09:54] 	 user2 is now known as `apx
	[12:09:58] 	 You're now known as apx_
	[12:09:59] 	 user3 is now known as `apx`

Cheers