feat(chatty): Optimize thread/reply collapse.

Switch to event based if statements that only evaluate on event, significantly reducing watch count.
fix(chatty): Remove unneeded TODO
fix(chatty): Simplify parent scope vars.
fix(chatty): Enable evented if statements for truncate.
fix(chatty): Switch reply count in truncated display to one time binding.
fix(chatty): Switch reply count in truncated display to one time binding.
fix(chatty): Replies not being updated.
fix(chatty): Improve perf with more one time bindings.
fix(chatty): Reduce watchers.

Implement evented-if for reply box open/close.
fix(chatty): More one time bindings.
fix(chatty): Fix new root post not closing properly.