generate splm format panel data issue in sur_utils.py

[lixun910]

The function
"""
def sur_dictxy(db,y_vars,x_vars,space_id=None,time_id=None):
"""
in sur_utils.py doesn't use the space_id at all to create splm format panel data. It doesn't work on the data organized like in nat_st_time.dbf: