Changes

Summary

1. merged
2. tuned attributes to avoid looping
3. added eq_iff_swap for creating symmetric variants of thms; applied it in List.
4. tuned text;
5. more robust timeout, following df4449c6eff1;
6. more accurate Files.isRegularFile, exclude directories (e.g. jar_path);
7. proper java_version for isabelle_setup;