Cltk

An overhaul of how the CLTK does lemmatization, now for Greek as well as Latin. Code for how lemma-headword dict is built for [Greek](https://github.com/cltk/greek_lexica_perseus/blob/master/transform_lemmata.py) and [Latin](https://github.com/cltk/latin_pos_lemmata_cltk/blob/master/transform_lemmata.py).

Added a word tokenizer specific to the Latin language. Mainly useful for separating enclitics -ve, -que, -ne from words. A Greek version is in the works.

Adds stopword builder.

- add several Tibetan corpora (per ticket 77)
- comment out old, pre-Git importer code

• Add Latin syllabifier (by Luke Hollis)
• add concordance maker
• add Chinese, Coptic, and Pali corpora

Overhaul of importers to use Git for corpus download and, now, update. The one known bug here is the Latin lemmatizer not working, which will get fixed soon.