Fixed #75. Add Classification to issue page.
Don't show extra info if there is none.

It looks ugly when we have an empty td whe extra info
is not provided.
Fixed #80. Exposes attack-releated detail in issue page.
Fixed #81. Don't display classification unless one of the ids is present.

Ideally we want to display that (even as Unknown), but the wording and
appearance wise, I think this row should be hidden IF neither ids are present.
Merge pull request #79 from yeukhon/enhance-output

Fixed #75. Fixed #80. Fixed #81. Expose attack and reference details.