Version 0.4
-------------

    - More logical set of SK AST nodes, proper handling of Let nodes
    - Support for Pipeline objects

Version 0.3-0.3.1
-------------

    - Multi-stage Excel code generation

Version 0.2
-------------

    - Multi-stage SQL code generation

Version 0.1
-------------

    - First prototype. Supports:
      * Inputs: linear models, trees, random forest and gradient boosting (partial)
      * Outputs: string, python, excel, sqlalchemy, sympy

