Patch for /trunk/README.txt

```
Typo
```

Original issue reported on code.google.com by `farizrah...@gmail.com` on 19 May 2015 at 4:05

Attachments:
- [README.txt.patch](https://storage.googleapis.com/google-code-attachments/word2vec/issue-30/comment-0/README.txt.patch)
