fix for ImportError: No module named GameManager

I tried running "python NausicaaRL.py" and got this error:

Traceback (most recent call last):
  File "NausicaaRL.py", line 1, in <module>
    from NausicaaRL.NausicaaRL import NausicaaRL
  File "/Users/Trystan/Projects/python/NausicaaRL/7drl/NausicaaRL/NausicaaRL.py", line 4, in <module>
    from nEngine.GameManager import GameManager