Added new files for pytest

* setup.py contains a new test command, starting runtests.py
* runtests.py imports pytest and starts the test process
* conftest.py is for future additions for pytest
Added .gitignore to ignore unneeded files
Set executable bit
Added new test: test_version

checks, if version number in last line of help output is available
Added tests_require
Moved from distutils to setuptools module

Integrated setuptools test command instead of distutils
Added new test: test_scipy

Checks, if the module scipy is available
Added main function

Prepare for importing this file as a module
Refactored to use it as a module

* Split main function into a main part and compare function
* Used exception handling to mark comparison as fail