tickit_term_ref() increments the stored refcount of the given terminal instance by one. It returns the
pointer argument itself, so it is useful for chaining.
tickit_term_unref() decrements the stored refcount of the given terminal instance by one. If the refcount
drops to zero, the instance is destroyed. This will release any resources controlled by it and unbind all
the bound event handlers, causing handlers to be invoked with the TICKIT_EV_DESTROY flag if appropriate.
It will not close any filehandles associated with the instance.