Adapt parser to new schema

see: #121
My vote is for multiple user_snps - different SNP arrays give slightly different results, for example, sometimes file A's user_snp is missing and B's is present, or A's user_snp is G and B's user_snp is from the opposite strand, so a C. It's very hard to keep in memory which of these are supposed to be the "right" one so I'd rather have both.