Terminal not always resized on navigation

[willemv]

In Safari, it seems like the connectedCallback of the FitAddon is often called before the terminal is fully initialized

This means the element of the terminal is still undefined when the first fit() is triggered, in which case the fit addon will not propose any dimensions.

This can be solved by adding a listener for the terminal-initialized event, and triggering a fit in response to that event.

[javier-godoy]

Hello. I had identified a similar issue with Chrome. In my application the issue happened rather often. The changes from #44 help preventing that situation, but don't eliminate it completely: now it only happens sometimes on the first load, and hardly ever on subsequent loads (in my case XTerm is displayed inside of a dialog).

I'm keeping this issue open since it clearly needs more analysis and a better fix, but for now your patch improves the situation a lot, and your diagnosis is correct: it is a timing issue and fit should be called after the component is fully initialized.