Improve stability and usability of JSR as a library

[Lms24]

The ultimate goal would be to improve JSR in terms of stability and usability to make it more comofortable to use it.

• Integrate Slicer4J into the project by removing the necessety to clone the repository and to build it plus the runner(s). As long as Sl4J is not a library, this means that we have to somehow include all necessary Jars from Sl4j in our project. This requires an updating mechanism of the jars but it is still much more stable and user friendly than expecting anyone to complete the tough install procedure that is currently necessary.
• Afterwards, reduce the number of user parameters (paths). We can easily drop the slicer path (as it would be directly included in the JSR Jars), possibly also the base backage parameter by finding the biggest common bases package when parsing the source code.
• Add options for a more step-by-step execution process by exporting every step's result (e.g. parsed representations of code/test sources are not persisted at the moment) and being able to continue where the user left off.