Improve get_data function
Improve get_data function

Library paths are all inserted at the beginning of sys.path, then
removed when the PyOpenWorm package is found.


Former-commit-id: bfa414a65b45247a0648f9398496ec09e30b3999
openworm/PyOpenWorm,kaustubhcs/PyOpenWorm,openworm/PyOpenWorm,hnunner/PyOpenWorm,travs/PyOpenWorm,gsarma/PyOpenWorm,gsarma/PyOpenWorm