Move `entities.json` to `data` folder

Thanks to @ForbesLindesay who suggested restructuring the folders.
Add script that parses the table in section 12.2.4.69

See http://whatwg.org/html/tokenization.html#tokenizing-character-references. Ref. #4.
Move `src/data.js` to the `scripts` folder
Add tests for #4
Make `grunt build` handle entities.json & table.js
Remove `grunt-curl` dependency
Implement the lookup table from the HTML spec

Fixes #4.
Update the code coverage report
Tag the v0.1.9 release