Modify code so that we now use a ListView (with a custom adapter) to
handle displaying the tips (since this is basically what it was made
for). Also, there is now a loading indicator when tip calculations are
being performed (these calculations now happen in a separate thread as
well).

Not sure how I feel bout the loading indicator right now. It shows up or
a split second in a lot of cases, which is visually jarring. May need
some more thought.
Update app name and icon