[DOC] more details about genotype columns.
[DOC] more details about genotype columns.

heuermh/gemini,xuzetan/gemini,arq5x/gemini,bgruening/gemini,udp3f/gemini,bpow/gemini,brentp/gemini,udp3f/gemini,brentp/gemini,heuermh/gemini,arq5x/gemini,bw2/gemini,heuermh/gemini,udp3f/gemini,udp3f/gemini,brentp/gemini,brentp/gemini,bpow/gemini,xuzetan/gemini,bgruening/gemini,xuzetan/gemini,bgruening/gemini,heuermh/gemini,arq5x/gemini,bw2/gemini,xuzetan/gemini,bgruening/gemini,bpow/gemini,bpow/gemini,bw2/gemini,bw2/gemini,arq5x/gemini