bump to v0.5.1b
bump to v0.5.1b

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