fixing the CLI option for sparkMaster in README
fixing the CLI option for sparkMaster in README

fixing an incorrect option name in the spark documentation in the README
frank-y-liu/gatk,magicDGS/gatk,magicDGS/gatk,broadinstitute/hellbender,frank-y-liu/gatk,broadinstitute/hellbender,magicDGS/gatk,magicDGS/gatk,ksthesis/gatk,frank-y-liu/gatk,frank-y-liu/gatk,frank-y-liu/gatk,broadinstitute/hellbender,ksthesis/gatk,magicDGS/gatk,ksthesis/gatk,broadinstitute/hellbender,ksthesis/gatk,broadinstitute/hellbender,broadinstitute/hellbender,magicDGS/gatk,ksthesis/gatk,ksthesis/gatk,frank-y-liu/gatk