Revision 163696

o Fixing a NullPointerException in the value extractor if the specified getter
  didn't exists. The value extractor will now return null if the getter doesn't
  exists.
o Properly implemented the method caching in the value exctrator.
o Changed the RegexBasedModelInterpolator so it would properly handle null
  values. It used to convert null to "null" and then insert that, now it will
  leave the expression as is.