* use encoding/json for comment parsing
* refactor by moving loop code to an UnmarshalJSON
* use a preallocated array and indices to maintain order while using
goroutines again, this was removed a while ago
* use new struct in comment.hbs and contextComment.hbs
* rewriteUrl partial to reduce rimgo-specific code in api
* move RenderError into pages package to avoid import cycle between render and utils