Update README.md, add two extra enviroment variables in 'Running Samples' section, remove unrequired env variable 'SCALA_HOME'
Update README.md, add two extra enviroment variables in 'Running Samples' section, remove unrequired env variable 'SCALA_HOME'

hebinhuang/Mobius,Microsoft/SparkCLR,danielli90/SparkCLR,dwnichols/Mobius,skaarthik/SparkCLR,tawan0109/SparkCLR,hebinhuang/Mobius,kai-zeng/Mobius,hebinhuang/Mobius,skaarthik/SparkCLR,tawan0109/SparkCLR,skaarthik/Mobius,cyruszhang/SparkCLR,xiongrenyi/SparkCLR,cyruszhang/SparkCLR,danielli90/SparkCLR,kai-zeng/Mobius,danielli90/SparkCLR,dwnichols/Mobius,kai-zeng/Mobius,hebinhuang/Mobius,Microsoft/SparkCLR,skaarthik/Mobius,tawan0109/SparkCLR,skaarthik/SparkCLR,skaarthik/Mobius,skaarthik/Mobius,dwnichols/Mobius,dwnichols/Mobius,dwnichols/Mobius,tawan0109/SparkCLR,xiongrenyi/SparkCLR,xiongrenyi/SparkCLR,skaarthik/Mobius,kai-zeng/Mobius,kai-zeng/Mobius,hebinhuang/Mobius,xiongrenyi/SparkCLR,skaarthik/Mobius,Microsoft/SparkCLR,cyruszhang/SparkCLR,dwnichols/Mobius,tawan0109/SparkCLR,kai-zeng/Mobius,xiongrenyi/SparkCLR,danielli90/SparkCLR,hebinhuang/Mobius,danielli90/SparkCLR