Fix CoreErrorsDialogModel adding duplicate errors.

Remove use of WeakList.

This is fairly trivial to implement with streams/lambdas,
no need to have our own hand-rolled list implementation
for it.

Fix CME in ConfigManager.removeListeners.

Fixes #521
Fixes #522

Use Multimap instead of MapList.

Tidy up DisplayProperty a bit.

Finish removing sendwho functionality.

Allow things to stop events displaying.

Make more server events use the new formatter.

Remove split user mode handling.

Make some server events use the new formatter.

Remove who settings.

Switch to J8 Base64.

Remove channel who functionality.

This will go in a plugin instead.

Split giant method up.

Allow null message, avoid exploding event handlers.

Stop recursively publishing errors if things break

Fix NPE when trying to add timestampless lines.

Think we're going to stop supporting this. If there's a decent
case for it then it should be done as a DisplayProperty instead.

Use GroupChat in events.

Add some alias tests.

Replace Channel with GroupChat in commands.

(This depends on a plugins change)

Dont raise invocationtargetexceptions I see raise the exception itself.

Synchronise access to maplist.

Fixes #500

Bug fixes for the profiles dialog.