Tweak and speed up gtk speller usage on chat window opening
Now every time chat window is opened in ChatControlBase.set_speller() loop is run to remove non-existent dictionaries from chat_control.dicts. Apart from that this routine should be called only once somewhere i suppose and not on every chat window open also spell.set_language(lang) call is quite expensive and could take up to ~0.5 sec here on the Russian language. And now multiply that by every chat window opening - that is quite distracting.
So attaching below simple patch to solve these issues.