[scikit-learn] Label encoding for classifiers and soft targets

[Gael Varoquaux]

> Would it be simple to modify sklearn code to do this, or would it require a lot of tinkering 
> such as modifying every single classifier under the sun? 

You can use sample weights to go a bit in this direction. But in general,
the mathematical meaning of your intuitions will depend on the
classifier, so they will not be general ways of implementing them without
a lot of tinkering.