precodeforSparkRInterpreter

What is this PR for?

Added parameter zeppelin.pyspark.precode to SparkRInterpreter. This is snippet of code which executes when interpreter initialize.

What type of PR is it?

Feature

What is the Jira issue?

https://issues.apache.org/jira/browse/ZEPPELIN-2228

How should this be tested?

1. Set parameter zeppelin.R.precode precodeVar=1+2


2. Run

Questions:

• Does the licenses files need update? no


• Is there breaking changes for older versions? no


• Does this needs documentation? no

该提问来源于开源项目：apache/zeppelin