Changes

Summary

1. tuned defs and proofs
2. tuned;
3. back to normal;
4. use min_height as in (much of?) the literature
5. use alternative server: https://isabelle.in.tum.de/components is down;
6. merged
7. back to dynamic library_call: not quite portable, e.g. different Windows installations (see e0c6522d5d43, 7cb68b5b103d)
8. bundle mixins for locale and class specifications
9. proper build_call for interpreted ARM platform;
10. prefer static library_call, following recent changes to structure Foreign;
11. updated to polyml-test-cf46747fee61 --- follow current ongoing development, with notable changes to structure Foreign;