Rebase of 6b791cd onto devel, without DeleteCardList activity.
Ticket63, alternate design

Added checkboxes to the left side of BaseballCardList's ListView.
Added a "Delete Cards" menu option which deletes marked cards.

Rebase onto devel branch.
Ticket63, alternate, updated

Removed long click listener, added a custom cursor adapter, users can
now select checkboxes by clicking them. Rewritten all tests to work with
alternate version.
Ticket63, alternate, javadocs

Added missing javadocs.