I2C: generate STOP in case of NACK (fix #698, #254)
I2C: generate STOP in case of NACK (fix #698, #254)

thanks @petrd and @Yazzcat

toastedcode/esp8266-Arduino,jes/Arduino,NullMedia/Arduino,wemos/Arduino,KaloNK/Arduino,lrmoreno007/Arduino,hallard/Arduino,Juppit/Arduino,gguuss/Arduino,hallard/Arduino,Adam5Wu/Arduino,me-no-dev/Arduino,Adam5Wu/Arduino,Adam5Wu/Arduino,sticilface/Arduino,hallard/Arduino,CanTireInnovations/Arduino,toastedcode/esp8266-Arduino,sticilface/Arduino,chrisfraser/Arduino,gguuss/Arduino,edog1973/Arduino,jes/Arduino,quertenmont/Arduino,Lan-Hekary/Arduino,esp8266/Arduino,edog1973/Arduino,gguuss/Arduino,chrisfraser/Arduino,KaloNK/Arduino,Juppit/Arduino,wemos/Arduino,Juppit/Arduino,quertenmont/Arduino,esp8266/Arduino,hallard/Arduino,martinayotte/ESP8266-Arduino,Links2004/Arduino,KaloNK/Arduino,esp8266/Arduino,Lan-Hekary/Arduino,toastedcode/esp8266-Arduino,lrmoreno007/Arduino,gguuss/Arduino,Links2004/Arduino,NextDevBoard/Arduino,NextDevBoard/Arduino,Juppit/Arduino,esp8266/Arduino,Adam5Wu/Arduino,KaloNK/Arduino,toastedcode/esp8266-Arduino,martinayotte/ESP8266-Arduino,CanTireInnovations/Arduino,lrmoreno007/Arduino,quertenmont/Arduino,jes/Arduino,Lan-Hekary/Arduino,NullMedia/Arduino,me-no-dev/Arduino,Links2004/Arduino,NextDevBoard/Arduino,jes/Arduino,lrmoreno007/Arduino,Lan-Hekary/Arduino,CanTireInnovations/Arduino,toastedcode/esp8266-Arduino,quertenmont/Arduino,martinayotte/ESP8266-Arduino,sticilface/Arduino,wemos/Arduino,gguuss/Arduino,martinayotte/ESP8266-Arduino,sticilface/Arduino,NullMedia/Arduino,Links2004/Arduino,KaloNK/Arduino,NextDevBoard/Arduino,edog1973/Arduino,wemos/Arduino,sticilface/Arduino,edog1973/Arduino,chrisfraser/Arduino,NextDevBoard/Arduino,esp8266/Arduino,Juppit/Arduino,chrisfraser/Arduino,edog1973/Arduino,Adam5Wu/Arduino,quertenmont/Arduino,wemos/Arduino,CanTireInnovations/Arduino,hallard/Arduino,Lan-Hekary/Arduino,me-no-dev/Arduino,martinayotte/ESP8266-Arduino,jes/Arduino,NullMedia/Arduino,me-no-dev/Arduino,Links2004/Arduino,chrisfraser/Arduino,CanTireInnovations/Arduino,NullMedia/Arduino,CanTireInnovations/Arduino,me-no-dev/Arduino,CanTireInnovations/Arduino,lrmoreno007/Arduino