Testrunner updates

test runner adjustments

• passing --batch to GDB to ensure we never are in "hidden gdb halt"
• let the tests run with the local cobcd.py (embedding may be disabled / not available)
• let the tests run with the local cobcd-rw, not the installed one
• fix tests not running without python3 (now configureable via PYTHON variable)
• optical only: switch "known-good" "testout" for diff

additional: update to replacing of version string

• now ignores CRLF in version.h
• now errors if no parameter passed
• output only: minimal nicer