Improve cross-platform support for JFreeChart
Currently TRACE4CPS is only tested on Windows, using Java8. There are known 'freeze' issues on Linux. These are most likely related to the Swing/SWT integration.
This integration is also sensitive for Java versions, as the code explicitly checks for a Java version (see #16 (closed)).
We should validate TRACE4CPS at least on Windows and Linux
and all long-term-supported Java releases > Java8. This requires improvements and first of all testing.