Allow to delete screenshots and app versions in app edit mode

Merged username-removed-26331 requested to merge grote/repomaker:ui-fixes into master
  • Make file upload functional and hide drag and drop texts
  • Prevent next/prev app URLs from jumping to different repos
  • Force encoding to UTF-8 when writing repo page to file (#76 (closed))

Closes #30 (closed)

Edited by username-removed-26331