plist is missing files

[fbergmann]

we've been made aware that setup.py install --record plist.txt is incomplete and missing the following files:

%%PYTHON_SITELIBDIR%%/libsbml/__init__.py
%%PYTHON_SITELIBDIR%%/libsbml/__pycache__/__init__%%PYTHON_EXT_SUFFIX%%.opt-1.pyc
%%PYTHON_SITELIBDIR%%/libsbml/__pycache__/__init__%%PYTHON_EXT_SUFFIX%%.pyc

not yet sure how to solve this, so filing it here for now.