!use python utility library to generate drag coefficient for ICOGS 3D

1). Install Python library on your system: git clone git@github.com:wzhengui/pylibs.git 

2). Add PYTHONPATH environmental variable to the python libaray
   e.g. on C-Shell: setenv PYTHONPATH 'YourDir/pylibs/Scripts/:YourDir/pylibs/Utility/' 

3). Double check the inputs in write_drag.py (at the bottom of the file)

4). Run the code to generate drag.gr3: ./write_drag.py
