Automatically cleaning unicode text about datacleaner

[rhiever]

Sounds promising. Please submit a PR with the new functionality along with unit tests to demonstrate how it works.

[dimenwarper]

I've implemented a draft of this but realized it may clash with the functionality of converting all text to numerical values. I wonder how to proceed, as I see it there are two options:

1. Fix the text before applying the encoding: This is what I'm doing right now, so strings like >=50 and >=50'get encoded to the same label.
2. Make encoding optional: This is tricky, there will be some text-based columns where you want to preserve the text to featurize later (e.g. with a sklearn.feature_extraction.text.TfidfVectorizer) rather than convert them to a label with an encoder. The tricky part is how to specify what columns you want to encode or not.

One way to proceed would be to go with 1 and then tackle 2 in a later issue.