Hints for cantor in main

Hints

• metainfo-validation-hint
  Validation of the metainfo file yielded the following hint: Consider using a secure (HTTPS) URL for 'http://edu.kde.org/cantor/'
• metainfo-validation-hint
  Validation of the metainfo file yielded the following hint: Consider using a secure (HTTPS) URL for 'http://docs.kde.org/stable/en/kdeedu/cantor/index.html'
• metainfo-validation-hint
  Validation of the metainfo file yielded the following hint: The component summary should not end with a "." [Matematiksel Yazılım için bir KDE Önyüzü.]
• metainfo-validation-hint
  Validation of the metainfo file yielded the following hint: Consider using a secure (HTTPS) URL for 'http://kde.org/images/screenshots/cantor.png'