This commit is also a stepping-stone towards handling http requests
which will require deferred callbacks on Yew Components. By figuring
out how to delay callbacks in this commit, it should be easier to
figure out how to handle http requests that may require a deferred
callback.
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).
