v0.5.0

Changes:

1. Multi language support (157 languages; using facebook's fasttext word vectors)
2. A program for converting fasttext models for use in sgrep
3. Better memoization - some speedup
4. Descriptive model load errors
5. Changed default model to glove in config.json
6. Added models to the repo for download along with License and Attributions
7. Internal changes to model management