* allow several classes in one source file with doc for each. Documentation in front of a class' ClassImp() invocation will be used; if there is none, the first one in the file will be taken (see e.g. TH1F etc: shared doc for all classes).
* convert the class doc parsing into a state machine which fixes a few cases where THtml was "forgetting" to write the class doc.
* fix a span for namespaces.
* Strip() now also removes newlines.
* clear un-used comments; fixes rare problem with misinterpreted comments.


git-svn-id: http://root.cern.ch/svn/root/trunk@21326 27541ba8-7e3a-0410-8455-c3a389f83636