Upgrade sentence segmentation to spacy

[ck37]

I think it would be good to upgrade the sentence segmentation to use spacy:
https://spacy.io/usage/linguistic-features#sbd

nlp = spacy.load("en_core_web_sm")
doc = nlp(u"This is a sentence. This is another sentence.")
for sent in doc.sents:
    print(sent.text)