Fix blank line between comments issue

[dane-johnson]

Related Ticket(s)

NA

Short roundup of the initial problem

If there existed a blank line in between comments before the first card, all cards were interpreted as sideboard. (This is the way deckstats.net exports cards decks with no sideboard).

What will change with this Pull Request?

• Sideboard will only begin after one mainline card and a blank space
• Test case added to prevent regression

[Daenyth]

Thanks so much for adding a test. Our coverage is embarrassing, so this helps a lot :)

[ZeldaZach]

Haha nice :)