This is a port of the NRLMSISE-00 atmospheric model to python 
based of the c version from Dominik Brodowski http://www.brodo.de/english/pub/nrlmsise/

It is used the same way as the c version is

C program runtime
0.031-0.033 seconds

Python runtime
0.038-0.041 seconds

It runs at almost comparable speeds after running a few times

To use, make an input class, and output class, and a flag class.
Set the input and flags with the appropriate settings,
then call gtd7(input, flags, output)
