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* Add first draft of annotation standards doc

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====================
Annotation Standards
====================
This document describes the target annotations spaCy is trained to predict.
This is currently a work in progress. Please ask questions on the issue tracker,
so that the answers can be integrated here to improve the documentation.
https://github.com/honnibal/spaCy/issues
English
=======
Tokenization
------------
Tokenization standards are based on the OntoNotes 5 corpus.
The tokenizer differs from most by including tokens for significant whitespace.
Any sequence of whitespace characters beyond a single space (' ') is included
as a token. For instance:
>>> from spacy.en import English
>>> nlp = English(parse=False)
>>> tokens = nlp(u'Some\nspaces and\ttab characters')
>>> print [t.orth_ for t in tokens]
[u'Some', u'\n', u'spaces', u' ', u'and', u'\t', u'tab', u'characters']
The whitespace tokens are useful for much the same reason punctuation is --- it's
often an important delimiter in the text. By preserving it in the token output,
we are able to maintain a simple alignment between the tokens and the original
string, and we ensure that the token stream does not lose information.
Sentence boundary detection
---------------------------
Sentence boundaries are calculated from the syntactic parse tree, so features
such as punctuation and capitalisation play an important but non-decisive role
in determining the sentence boundaries. Usually this means that the sentence
boundaries will at least coincide with clause boundaries, even given poorly
punctuated text.
Part-of-speech Tagging
----------------------
The part-of-speech tagger uses the OntoNotes 5 version of the Penn Treebank
tag set. We also map the tags to the simpler Google Universal POS Tag set.
Details here: https://github.com/honnibal/spaCy/blob/master/spacy/en/pos.pyx#L124
Lemmatization
-------------
A "lemma" is the uninflected form of a word. In English, this means:
* Adjectives: The form like "happy", not "happier" or "happiest"
* Adverbs: The form like "badly", not "worse" or "worst"
* Nouns: The form like "dog", not "dogs"; like "child", not "children"
* Verbs: The form like "write", not "writes", "writing", "wrote" or "written"
The lemmatization data is taken from WordNet. However, we also add a special
case for pronouns: all pronouns are lemmatized to the special token -PRON-.
Syntactic Dependency Parsing
----------------------------
The parser is trained on data produced by the ClearNLP converter. Details of
the annotation scheme can be found here:
http://www.mathcs.emory.edu/~choi/doc/clear-dependency-2012.pdf
Named Entity Recognition
------------------------
+--------------+-----------------------------------------------------+
| PERSON | People, including fictional |
+--------------+-----------------------------------------------------+
| NORP | Nationalities or religious or political groups |
+--------------+-----------------------------------------------------+
| FACILITY | Buildings, airports, highways, bridges, etc. |
+--------------+-----------------------------------------------------+
| ORGANIZATION | Companies, agencies, institutions, etc. |
+--------------+-----------------------------------------------------+
| GPE | Countries, cities, states |
+--------------+-----------------------------------------------------+
| LOCATION | Non-GPE locations, mountain ranges, bodies of water |
+--------------+-----------------------------------------------------+
| PRODUCT | Vehicles, weapons, foods, etc. (Not services) |
+--------------+-----------------------------------------------------+
| EVENT | Named hurricanes, battles, wars, sports events, etc.|
+--------------+-----------------------------------------------------+
| WORK OF ART | Titles of books, songs, etc. |
+--------------+-----------------------------------------------------+
| LAW | Named documents made into laws |
+--------------+-----------------------------------------------------+
| LANGUAGE | Any named language |
+--------------+-----------------------------------------------------+
The following values are also annotated in a style similar to names:
+--------------+---------------------------------------------+
| DATE | Absolute or relative dates or periods |
+--------------+---------------------------------------------+
| TIME | Times smaller than a day |
+--------------+---------------------------------------------+
| PERCENT | Percentage (including “%”) |
+--------------+---------------------------------------------+
| MONEY | Monetary values, including unit |
+--------------+---------------------------------------------+
| QUANTITY | Measurements, as of weight or distance |
+--------------+---------------------------------------------+
| ORDINAL | "first", "second" |
+--------------+---------------------------------------------+
| CARDINAL | Numerals that do not fall under another type|
+--------------+---------------------------------------------+