In python reader, close and open file when re-reading.

This fixes FGE bug 173
Use b->station_names, when constructing a dictionary of time histories.
Delete debugging print statement.
Fix package_dir keyword.

Should be a dictionary.
Don't call Py_DECREF on borrowed references.

...that can cause segfaulting.
PyList_GetItem returns a borrowed reference, which means that the
reference count isn't incremented.