JSON fix: give pre_print_temp and post_print_temp back their default_temp
JSON fix: give pre_print_temp and post_print_temp back their default_temp

Curahelper/Cura,ynotstartups/Wanhao,ynotstartups/Wanhao,hmflash/Cura,fieldOfView/Cura,Curahelper/Cura,hmflash/Cura,fieldOfView/Cura