avoid self-closing elements in html. fix for #473 (#474)
avoid self-closing elements in html. fix for #473 (#474)


playi/pxt,switch-education/pxt,switchinnovations/pxt,switchinnovations/pxt,Microsoft/pxt,switch-education/pxt,playi/pxt,switchinnovations/pxt,switchinnovations/pxt,switch-education/pxt,playi/pxt,Microsoft/pxt,playi/pxt,Microsoft/pxt,Microsoft/pxt,Microsoft/pxt,switch-education/pxt,switch-education/pxt