fix(change-detector): handle double.NAN for collections (in JS)
fix(change detector): fix the handling of NaN & string values for maps
style: code cleanup
refactor: improve code readability
fix(http_spec): implement lastModified getter
chore(scope): add assert that scope is attached
feat(scope): add internal streams consistency checks
fix(change-detection): corrected adding group to sibling which had children
fix(WatchGroup): don't call reaction functions on removed WatchGroups