fixed a absolute_import problem in surface.py
fixed a absolute_import problem in surface.py

eayoungs/eppy,santoshphilip/eppy,santoshphilip/eppy,santoshphilip/eppy,jamiebull1/eppy,jamiebull1/eppy,jamiebull1/eppy,eayoungs/eppy,eayoungs/eppy