Hints for ngraph-gtk in main

Hints

• asv-cid-contains-hyphen
  :4 - com.github.htrb.ngraph-gtk
  The component ID contains a hyphen/minus. Using a hyphen is strongly discouraged, to improve interoperability with other tools such as D-Bus. A good option is to replace any hyphens with underscores (`_`).
• asv-url-not-secure
  :15 - http://hito.music.coocan.jp/ngraph/ngraph-gtk.html
  Consider using a secure (HTTPS) URL for this web link.
• asv-screenshot-media-url-not-secure
  :21 - http://hito.music.coocan.jp/ngraph/ngraph_609_linux.png
  Consider using a secure (HTTPS) URL to reference this screenshot image or video.
• asv-nonstandard-gnome-extension
  :25 - kudos
  This tag is a GNOME-specific extension to AppStream and not part of the official specification. Do not expect it to work in all implementations and in all software centers.