fix camel cases in ppkts

[aslgraefe]

in eval cohort, the blocks do not have camel case as a header altohugh processable in gpsea.

Also, zygosity had to be lower letters to be read properly for some reason in GPSEA, to read the cohort. either a problem in the GENO code or the capitalisation?

also change GENO:0000458 for simple heterozygosity to the normal GENO:0000135? label_dicts.py?

[aslgraefe]

finished with #211 #208