Adding Sample Name / Caller name

[karthigayini]

For future us - Need to add Sample name/ caller name in the Final merge step and at maf_sub

#mafdf_sub=maf_df[['Chromosome', 'Start_Position', 'End_Position','Reference_Allele', 'Tumor_Seq_Allele1', 'Tumor_Seq_Allele2']]

#final_annotate = combined_annotations.merge(maf_df, on=['Start_Position','End_Position', 'Chromosome','Reference_Allele', 'Tumor_Seq_Allele1', 'Tumor_Seq_Allele2'], how='right')