1.0.0-rc1

• Added Token Hashing Vectorizer transformer
• Added Word Stemmer tokenizer from Extras
• Remove HTML Stripper and Whitespace Remover transformers
• Rename steps() method to losses()
• Steps() now returns iterable progress table w/ header
• Remove rules() method on CART
• Removed results() and best() methods from Grid Search
• Change string representation of NAN to match PHP
• Added extra whitespace pattern to Regex Filter