Converted BVSCalculator methods value, valences, bvdiff, bvmsdiff, bvrmsdiff

to properties.

Author: pavoljuhas

diffpy/srfit/structure/bvsrestraint.py

@@ -66,7 +66,7 @@ def penalty(self, w = 1.0):
         """
         # Get the bvms from the BVSCalculator
         self._calc.eval(self._stru)
-        penalty = self._calc.bvmsdiff()
+        penalty = self._calc.bvmsdiff
 
         # Scale by the prefactor
         penalty /= self.sig**2