Revert "Element#root"

This reverts commit 78a576fc93b279c4b7fea4a4381b21b893d137df.
get rid of override warnings in ElementStub
do not search descendants of Root
find by :id & :name return nil if not found
refactor how to null check for ElementInformation struct
specs around elements that fail to be found
refactor how find methods return nil
Element#find by :id or :name
finding by runtime id is always TreeScope::Descendants
extension method for string to be an Id or Name property