title: customizing Stanford-NER for detecting Actor, Director, production company names in movie reviews
body: <p>I want to train my model to detect the names of actor, director, production company from movie reviews. I have tokenized and tagged my dataset now, I have to set feature properties. I searched a lot about FeatureFactoryNER but I didn't find any reasonable way to completly understand this class. 
  My question is that how we can define our own features in FeatureFactoryNER in order to train the model in right way? Please help in understanding FeatureFactory, properties and defining customize features? </p>