Merging extra pylint tests into master
Fix defective pylint test
Fix defective pylint test
Change default set of includes for C tests to include <string.h> and <stdbool.h>
Fix problem of php out-of-memory with very large stdout/stderr files by (a) limiting nullsandbox output to 1M and (b) rewriting the validatorbase clean function to avoid use of the well-named "explode" function (which took a 10MB string to over 300MB!).
Fix bug in last commit: it didn't properly cleanse output string of binary junk, leading to "error writing to database" if C program ran off rails and printing binary".
Fix long-standing but hitherto unknown bug that resulted in an unnecessary regrading of all coderunner questions on quiz submission.
Merging in development stuff (ideone sandbox, mostly).
Merging in development stuff (ideone sandbox, mostly).
pylint test fix
Change CodeRunner behaviour to suppress regrading of already-graded questions at the end of a quiz. [Warning: this fix is somewhat tentative. In the longer term I'd prefer to run with whatever bug fix Tim Hunt implements for this problems, which should be documented in due course at https://tracker.moodle.org/browse/MDL-42399]
Tentative change to behaviour to force regrading whenever CHECK is clicked, even if the answer hasn't changed. [Solves problem of answers that are links to external resources and also of frustration with authors checking changed test data. But may introduce other issues.]
Fix all tests in which assertEquals parameters were the wrong way round. [Didn't affect correctness but could give confusing error messages.]
Improve handling of language types in ideone sandbox plus a couple of trivial commenting and formatting changes.
Tidy up question editing form and add variables to control display of results table.
Delete all stats handling, storing, generations etc. That was a failed experiment.
Mid-hacking commit in order to work with master for a bit
Alpha release state of all the changes required to support selection of which columns to display in results table, together with all the various improvements (hopefully) to the question editing form.