JSON: support bottom stair step height defaults changed so that the bottom distance to the model isn't violated too much
JSON: support bottom stair step height defaults changed so that the bottom distance to the model isn't violated too much

ynotstartups/Wanhao,markwal/Cura,Curahelper/Cura,markwal/Cura,fieldOfView/Cura,totalretribution/Cura,ynotstartups/Wanhao,Curahelper/Cura,hmflash/Cura,senttech/Cura,hmflash/Cura,fieldOfView/Cura,senttech/Cura,totalretribution/Cura