DOC move NER and Entity Grouping chapters out of parent section
HtmlToken.root attribute
Don't let __START/END_TAG__ special tokens appear in trees accessible from HtmlToken
make encoding argument optional for html_document_fromstring
start webstruct.webannotator module
HtmlTokenizer.detokenize_single method for undoing HtmlTokenizer.tokenize_single
WIP crfsuite support
some small refactor and document improvement
better stripping regex for __START/END_TAG__ tokens
WebAnnotator writer
workaround for lxml < 3.1.2
fix tostr in previous change
Less aggressive cleaning: preserve scripts and stylesheets, but don't produce HtmlTokens for them.
fix webstruct.webannotator handling of attributes that are valid in HTML but invalid in XML
make it possible to have consistent colors in to_webannotator function
abandon CRF++ template in CRFsuite backend

add a default features set for CRFsuite which demostrate how
to create bigram/trigram features with python rather than template.
fix test failures
implement ngrams as global feature function
allow WebAnnotatorLoader handle nested annotation by introducing known_tags to it
change known_tags to known_entities and make it optional for WebAnnotatorLoader