[BUG] allow individual sample info from gt_* columns to be JSON serializable.
[BUG] allow individual sample info from gt_* columns to be JSON serializable.

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