There are two binaries here.  One was compiled on an Ubuntu 14.04
system.  The other was compiled on duecray.  Both give identical
results for the sample problem provided.

sample.input.csv is the file used as input (given to the '-i'
argument).

The other .csv files are the outputs the simulation created with it.
The simulation was run via:

  ./nbody -i sample.input.csv -n 4 -d 1.0 -t 0.1 -o 1 -e 0.1
