spellcheck tests, spellcheck organization
replaced existence test with trie
clarify function name, add tests for spelling corrector
Add tests for tfidf.
tests, consider smaller edit-distances more likely corrections than greater ones, comments
added documentation of spellcheck
add more documentation
Merge pull request #201 from johnmarkos/classifier-coverage

Coverage for lib/natural/classifiers/classifier.js
Merge pull request #200 from johnmarkos/tfidf_coverage

Add tests for tfidf.
Merge pull request #202 from mbc1990/spelling-corrector

Spellcheck
Add spec for remove_diacritics.
Merge pull request #203 from johnmarkos/remove-diacritics-coverage

Add spec for remove_diacritics.
Add tests for normalizer.js.
Merge pull request #204 from johnmarkos/normalizer-coverage

Add tests for normalizer.js.