unix: Properly print script filename in case of error.
showbc: Make sure it's possible to trace MAKE_FUNCTION arg to actual bytecode.
showbc: Make micropython -v also dump bytecode in hex form.
Add missing commas to stm32f4xx-af.csv
Merge pull request #651 from dhylands/fix-af-csv2

Add missing commas to stm32f4xx-af.csv
py: Instead of having "debug on" var, have "optimization level" var.

This allows to have multiple "optimization" levels (CPython has two
(-OO removes docstrings), we can have more).
py: For optimization level -O3 and higher, remove lineno info from bytecode.
vm: If there's no lineno info, set lineno in traceback to 0, not 1.

To clearly signify that lineno is not known.