tests/run.sh: Make meta test for all errstats.py tests. - Make all() automatically discover and run all valid tests.   - No more remembering to manually update it. - Separate and automatically list all meta tests in -h help. - Rename errstats() -> errstats_simple().
tests/run.sh: Make meta test for all errstats.py tests.
- Make all() automatically discover and run all valid tests.
  - No more remembering to manually update it.
- Separate and automatically list all meta tests in -h help.
- Rename errstats() -> errstats_simple().

makrutenko/dunovo,makrutenko/dunovo,makrutenko/dunovo