Adds command-line options -y and -n to cmsMake
cmsMake: do not set "assume" as global, but pass it in the calls stack.
cmsMake: even when assuming the answer, print the question anyway.

It is (TTBOMK) a common pattern and it helps understanding what's
going on.
Change cmsMake to also create a binary compiled with -DEVAL (sol/${NAME}_EVAL), and to use it for test_${NAME}.
cmsMake: fix some flaws in the _EVAL mechanism (as well as some previous bugs).
Allows generators and validators to be in C / C++ / Pascal too.
cmsMake: small fixes.
Change cmsMake to use argparse instead of the deprecated optparse
Allows compiled programs to use syscall 'dup3', as it already is in ./cms/grading/__init__.py
Add isolate to LICENSE.txt, and update from dep5
Make non-ASCII compile messages visible
Add new task tests to setup.py
Fix typo in a comment
Small fix to cms/grading/ParameterTypes.py
Many small fixes to the DB classes

Mostly comments and PEP8, but also some more serious things.
Small fixes to CWS
Remove cms/grading/AbstractionLayer.py

It was completely unused.
Some changes to ScoringService

- rename the 'submission_ids_*' sets to 'submissions_*'
- drop the token timestamp (and use just the submission id) inside the
  tuples that form the elements of the 'submissions_to_token' set
- don't use lists only to convert them to sets at the end, but start
  with sets from the beginning
- use 'get_from_id' instead of making a manual query
- some whitespace
Improve the 'invalidate_submission' methods of ES and SS

Mostly by rewriting get_submissions to return objects instead of IDs.
Reduce the use of export_to_dict and import_from_dict