Can place tokens, and not place tokens where there already is a token.
Additional info text box added to the side of the board.
More information to the UI regarding placed tokens.
Remove state::MessageBus in favor of String messages sent to Wrapper
from Slot.
Update Slot state from inside Wrapper::update such that changes should
be immediately visible per Slot (moved code from Wrapper::rendered,
fixing updates not being immediately visble).
Stephen Seo