Fix import error
Without this, one gets this error:
$ python3 python/FastFrames.py --config test/configs/config.yml --step h
Traceback (most recent call last):
File "/home/diptaparna/Documents/FastFramesTry/fastframes/python/FastFrames.py", line 23, in <module>
from ConfigReader import ConfigReader
ModuleNotFoundError: No module named 'ConfigReader'