[SPARK-7402] [ML] JSON SerDe for standard param types

This PR implements the JSON SerDe for the following param types: `Boolean`, `Int`, `Long`, `Float`, `Double`, `String`, `Array[Int]`, `Array[Double]`, and `Array[String]`. The implementation of `Float`, `Double`, and `Array[Double]` are specialized to handle `NaN` and `Inf`s. This will be used in pipeline persistence. jkbradley

Author: Xiangrui Meng <meng@databricks.com>

Closes #9090 from mengxr/SPARK-7402.