Changed the default unit for mass density to g/cm3

MDANSE/Framework/Jobs/Density.py

@@ -71,7 +71,7 @@ class Density(IJob):
 
         self._outputData.add("mass_density","line", (self._nFrames,), units='g/cm3')
 
-        self._outputData.add("atomic_density","line", (self._nFrames,), units='1/nm3')
+        self._outputData.add("atomic_density","line", (self._nFrames,), units='1/cm3')
 
         if not self.configuration['trajectory']['instance'].universe.is_periodic:
             raise JobError("Pair distribution function cannot be calculated for infinite universe trajectories")