General standard deck test coverage with couple bug fixes.

[ismemang]

Standard deck test coverage and to see that it was complete enough for me to use in another project. I ended up fixing what I believe to be a couple small bugs in _deck as well.

• Optional test results report.
• Optional test coverage report.
• Test coverage mainly of StandardDeck.

npm run test:unit
open report/test/unit/results/index.html
npm run test:unit:cover
open report/test/unit/coverage/index.html

# Help prove the bug fixes.
npm run test:unit -- --grep 'when the card is added to the deck'
npm run test:unit -- --grep 'when the two decks are merged'

[ismemang]

Would it be preferred that I break the bug (potential) fixes out into their own PR?

[kbjr]

No, this works fine for me.
Bug fix published in 2.0.2