Added typed getter/setter methods for RG attributes.
Added typed getter/setter methods for RG attributes.

broadinstitute/picard,annkupi/picard,annkupi/picard,alecw/picard,annkupi/picard,broadinstitute/picard,broadinstitute/picard,alecw/picard,nh13/picard,broadinstitute/picard,nh13/picard,broadinstitute/picard,nh13/picard,alecw/picard,nh13/picard,alecw/picard,annkupi/picard