With this fix introduced two new services, FindNodeById and
FindNodeWithId. The former does a total tree search for a TidyTagId.
Maybe there is a way to optimise this search...
Also change the uint badForm from an on/off to a bit field, so could be
extended to other document format errors.
An immense thanks to Ger Hobbelt who had already done this
in his github.com/GerHobbelt/htmltidy fork.
The two sources have diverges so was not a simple cut
an paste. But again thanks Ger for this.
