GM: move original genotype reader to genotype file dir that will hold other readers/writers
GM: factory to create a genotpye file reader
GM: make orignal genotype file reader just a tsv reader
GM: extracted reading of inst data genotype file into separate class
GM: writer factory to write genotype file
SRV: add param to fill in null value
GM: writer factory use \t for TAB; correctly sets defaults
GM: merge extract commands
GM: extract command genotype metrics fixed, get gm builds instead of models
GM: rm alleles prop from read tsv
GM: extract counts alleles
GM: fix sample type priority values, make resolve_source public
GM: remove instdata extract command, use model extract commmand
GM: do not set id from snp name in read tsv
GM: make the return value of read tsv and annotate consistent to read tsv
GM: extract command doc update
GM: merge reader test into one that will also test writing
GM: CSV writer
GM: make default headers a function in write csv
Utility: writer sets orginal output to - for STDOUT