Robust tracking of quoted and unquoted attributes

Requires https://github.com/tildeio/simple-html-tokenizer/pull/13

Instead of using the presence of a value as the identifier for a quoted state, track this in the tokenizer
> No. An array is used to differentiate foo={{bar}} from foo="{{bar}}". Array is the latter case. Array means concat.

One of the aims of tracking quoted is to remove the implicit concat. It seems like the old code is using array/non-array as a signal for quoted, but that isn't needed anymore.