cobcd: explicit set language English for parsing commands' output

This one was part of leading to "stuck GDB" when trying to run the testsuite - German messages generated by cobc were not matched by cobcd, to fix this we explicit set the language before calling commands which output cobcd tries to match.

additional: fixed some linter warnings

• copyright year and linter comments adjusted to match cobcd.py
• remove unused imports, removed/commented unused var
• remove ;