Add a source to displayable events.

Need this to figure out where to display them, for now.
Merge pull request #249 from csmith/master

Add a source to displayable events.
Merge pull request #250 from greboid/awaymessages

Make events use User.
Use new source method for displaying events.
Only set a FG colour if one isn't set already.
Merge pull request #251 from csmith/master

More work on events.
Merge pull request #252 from greboid/awaymessages

Fix unit test.
Merge pull request #254 from greboid/awaymessages

Tidy getUser methods in Server.
Initial work on highlight manager.

For now this just highlights the current nickname, but it can cope
with a list of other patterns once we decide how to store and model
them.

Also for now, sets the BG colour to red. Need to make that
configurable.

Issue #36
Doesn't need to be a strong listener any more.
Merge pull request #255 from csmith/master

Initial work on highlight manager.
Push some event handling into ServerEventHandler.
Merge pull request #256 from csmith/master

Push some event handling into ServerEventHandler.
Use User in Topic.
Merge pull request #257 from csmith/master

Use User in Topic.
Remove some more ClientInfo usages.