* modifying FR lookup to remove ambiguity and adding lookup vocab to FR files
* modifying FR lookup to remove ambiguity and adding lookup vocab to FR files
* updating the contributor agreement for amperinet
* adding adverbs and irregular cases for empty words
* adding adverbs and irregular cases for empty words
* adding adverbs and irregular cases for empty words
* updating contributor agreement for amperinet
* modifying French lookup that contained wrong lemmas
* correcting wrong line breaks on hyphen
* adding contributor agreement for amperinet@
* correcting a typo
* modifying FR lemmatization for nouns
* modifying FR lemmatization for nouns
* adding contributor agreement for amperinet
* adding rules for words with inclusive parentheses wrongly tokenized
* adding contributor agreement for amperinet
* adding a missing comma
* updating rules and vocabulary for French lemmatization of verbs
* updating the file with French auxiliary verb
* updating rules and vocabulary for French lemmatization of verbs
* adding contributor agreement for amperinet
* adding rules for words with inclusive parentheses wrongly tokenized
<!--- Provide a general summary of your changes in the title. -->
## Description
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testing, include information about the testing environment and the tests you
ran. If your test fixes a bug reported in an issue, don't forget to include the
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Add a rule-based French Lemmatizer following the english one and the excellent PR for [greek language optimizations](https://github.com/explosion/spaCy/pull/2558) to adapt the Lemmatizer class.
### Types of change
<!-- What type of change does your PR cover? Is it a bug fix, an enhancement
or new feature, or a change to the documentation? -->
- Lemma dictionary used can be found [here](http://infolingu.univ-mlv.fr/DonneesLinguistiques/Dictionnaires/telechargement.html), I used the XML version.
- Add several files containing exhaustive list of words for each part of speech
- Add some lemma rules
- Add POS that are not checked in the standard Lemmatizer, i.e PRON, DET, ADV and AUX
- Modify the Lemmatizer class to check in lookup table as a last resort if POS not mentionned
- Modify the lemmatize function to check in lookup table as a last resort
- Init files are updated so the model can support all the functionalities mentioned above
- Add words to tokenizer_exceptions_list.py in respect to regex used in tokenizer_exceptions.py
## Checklist
<!--- Before you submit the PR, go over this checklist and make sure you can
tick off all the boxes. [] -> [x] -->
- [X] I have submitted the spaCy Contributor Agreement.
- [X] I ran the tests, and all new and existing tests passed.
- [X] My changes don't require a change to the documentation, or if they do, I've added all required information.
