guess media type by filename extension when mimetype is missing
guess media type by filename extension when mimetype is missing

slr/twister-html,miguelfreitas/twister-html,xeddmc/twister-html,xeddmc/twister-html,myleneb/twister-html,miguelfreitas/twister-html,majestrate/twister-html,slr/twister-html,myleneb/twister-html,majestrate/twister-html