Challenges

Changing the naming conventions of the challenge class and the test case class. See message of previous commit.

Version 0.1.5

* Finetune the Readme.
* Bring links into rst style.
* Add status badge from readthedocs.
* Status informations within the head.

This version will by synchronised with the documentation build process at readthedocs.

A minor update of the README.

This version is the fist working public release. The previous releases have been withdrawn due to not working version file.