v0.2.0

Core structure was changed.

v0.1.1: New features were added.

Index can be specified by run method. Entry methods are using the run
method as a referance. Steps can be specified by prev and next methods
by this way.

v0.1.0

Clusters were collected at Entry class. There are two new methods as named next and prev.

v0.0.2

The dyslexic problem was fixed.

v0.0.1

Minor bug fixes.