[SPARK-2550][MLLIB][APACHE SPARK] Support regularization and intercept in pyspark's linear methods.

Related to issue: [SPARK-2550](https://issues.apache.org/jira/browse/SPARK-2550?jql=project%20%3D%20SPARK%20AND%20resolution%20%3D%20Unresolved%20AND%20priority%20%3D%20Major%20ORDER%20BY%20key%20DESC).
I used a type of Enumeration in order to separate between the different types of Update Methods [Regularizers] with which the user wants to create the model from training data. I tried to extend this object from Enumeration but from what I have seen it uses reflection heavily and it does not work well with serialized objects and with py4j...