Smarter brackets and tags completion

[Curculigo]

Currently, it will blindly insert the closing brackets and tags without considering the context.

[SpartanJ]

This is not easy and I don't think there's a way to implement it perfectly. Even with the context you cannot always infer the user intention, that's why I personally don't like most auto-close features (except for auto-close tags that it actually saves you time). There's currently some very basic logic to avoid auto inserting extra close brackets on some cases but it will not be enough. More info in issue #121.