Python 2 is end of life on 2020-01-01

[mr-c]

What's the plan for src/bin/{sga-align, sga-astat.py, sga-joinedpe, src/bin/sga-preqc-report.py}?

[jts]

I think sga-preqc-report.py should work with python3. sga-joinedpe is a small unimportant utility program. sga-align should be deprecated. sga-astat should be updated.