update copyright headers for new year

find pyhwp -iname '*.py' | xargs bin/gpl --add-year=2013
buildout: bootstrap.py for 1.x (fix #117)
java-poi: upgrade to 3.9 and change download url
buildout: pin to virtualenv 1.8.4 (see #118)
jenkins: execute if os.environ 'EXEC_BOOTSTRAP_PY' equals 'true'
jenkins: groovy script prints cmd