add FIXME for eccentricity variable names

src/orbits.cpp

@@ -158,6 +158,7 @@ ellipse3DUpdate(ellipse_parameters ep, ellipse_3d& e3d)
 // NOTE: propagate anomaly functions:
 //
 
+// FIXME: variable names 'ecc' should be just 'e'
 double
 getEccAnomFromTrueAnom(double ecc, double true_anom)
 {