Log Message:
devel/hs-validation-selective: import hs-validation-selective-0.2.0.0

Lightweight pure data validation based on Applicative and Selective
functors.

validation-selective is built around the following data type:

    data Validation e a
        = Failure e
        | Success a

This data type is similar to Either but allows accumulating all errors
instead of short-circuiting on the first one.