Allows a user to figure out a range of possible tips on the fly for paying a restaurant bill or anything else that requires a tip.
The top of the app has the bill total entered by the user from a keyboard
that is present at the bottom of the app. Below the bill total box are preset
ranges of 10%, 15% and 20% tip options followed by a custom scroller that
allows a person to put in a range from 0 to 30%. It is coded to a default
start of 18% on the slider.