Create README.md

User is displayed the tip of specified percentage for specified entered amount
User enters the total amount of the transaction
User can select between tip amounts (i.e 10%, 15%, 20%)
Upon selecting tip amount, formatted tip value is displayed
User changes the total amount and updated tip is reflected automatically
User can select custom tip percentage if desired
User can select how many ways to split the tip
User can edit preset tip percentages and have them persist across launches
Experiment with trying input widgets to replace the buttons and/or textviews
Improve the user interface and experience by using images and/or colors