Back to older pitest (0.29) it was compatible with Maven2 etc.
It's used in our Sonar plugin 0.2.
Closes #123
It was an interesting bug depending on order of tests execution.
Thanks to pitest which used different order than JUnit standard, the bug of influence of one test on another has been discovered and fixed.

During investigation I used @FixMethodOrder Junit annotation to have control over test order. In final version it's not needed
Graceful way to work with System properties: preserve their state before suite, restore (if needed) after suite.

To ensure the tests leave the environment as much as possible close to the initial state.