Merge pull request #39 from poseidon-framework/snpSet-non-mandatory-rollback

made snpSet non-mandatory, also changed README

Author: stschiff

POSEIDON_yml_fields.tsv

@@ -15,7 +15,7 @@ snpFile	1	genotypeData	relative path to snpFile	String	Path	TRUE	TRUE
 snpFileChkSum	1	genotypeData	md5 checksum of the snpFile	String		FALSE	TRUE
 indFile	1	genotypeData	relative path to indFile	String	Path	TRUE	TRUE
 indFileChkSum	1	genotypeData	md5 checksum of the indFile	String		FALSE	TRUE
-snpSet	1	genotypeData	Can be either 1240K, HumanOrigins or Other depending on the list of SNPs used	String	(1240K|HumanOrigins|Other)	TRUE	FALSE
+snpSet	1	genotypeData	Can be either 1240K, HumanOrigins or Other depending on the list of SNPs used	String	(1240K|HumanOrigins|Other)	FALSE	FALSE
 jannoFile	0		relative path to jannoFile	String	Path	FALSE	TRUE
 jannoFileChkSum	1	genotypeData	md5 checksum of the jannoFile	String		FALSE	TRUE
 bibFile	0		relative path to bibFile	String	Path	FALSE	TRUE

README.md

@@ -82,7 +82,7 @@ Genotype data in Poseidon packages is stored either in PLINK (binary) or EIGENST
 | SNP file  | [`.bim` (extended MAP file)](https://www.cog-genomics.org/plink/1.9/formats#bim) | [`.snp` (snp file)](https://github.com/DReichLab/EIG/blob/fb4fb59065055d3622e0f97f0149588eae630a3e/CONVERTF/README#L67) |
 | individual file  | [`.fam` (sample information)](https://www.cog-genomics.org/plink/1.9/formats#fam) | [`.ind` (indiv file)](https://github.com/DReichLab/EIG/blob/fb4fb59065055d3622e0f97f0149588eae630a3e/CONVERTF/README#L67) |
 
-In addition to these files and their checksums, you also must provide a `snpSet` entry which determines the shape of the genotype file. Currently, only `1240K`, `HumanOrigins` or `Other` are allowed.
+In addition to these files and their checksums, you also should provide a `snpSet` entry which determines the shape of the genotype file. Currently, only `1240K`, `HumanOrigins` or `Other` are allowed. While technically not a mandatory field, for backwards compatibility, we encourage users to set this field, and in fact our software also encourages this through required user input.
 
 ##  The `.janno` file