Changed the target directory for the downloaded Eigen headers so that they are now located within the build folder (hopefully avoiding conflicts with multiple build-folders).
Made the include path for the Eigen headers more unique, so we no longer use the headers at /urs/include/ instead.
- Scheduler export: Properly handle models with end components. Added export in .json format.
- CMake: Search for Gurobi prefers new versions
- CMake: We no longer ship xerces-c. If xerces-c is not found on the system, storm-gspn will not be able to parse xml-based GSPN formats
- `Eigen' library: The source code of Eigen is no longer included but downloaded from an external repository instead. Incremented Eigen version to 3.3.7 which fixes a compilation issue with recent XCode Versions.
- Tests: Enabled tests for permissive schedulers
- `storm-counterexamples`: fix when computing multiple counterexamples in debug mode
- `storm-dft`: Renamed setting `--show-dft-stats` to `dft-statistics` and added approximation information to statistics.