Display score based on game mode

[johneastman]

For both game modes, the high score is stored as a number, so we need to be able to determine whether that number represents time or number data.

• For Precision shot, the high score is a number
• For Quick Draw, the high score is a time
• Use this flag to properly display the high score for each game mode
• Game mode flag can be GameMode enum created in #52.

Initial Implementation Plan

1. Add a method to HighScore called getScore that returns the score as a string based on the data type flag (number or time).
2. Create a Score component that accepts as one of the props a HighScore object and calls getScore to display the score.
3. Rename HighScore to Score.
4. Use this Component for displaying both the running score and high scores.

Places the score need to be updated

• current/running score
• High scores
• Final score on end-game screen

[johneastman]

The implementation panned out differently than planned, but all the requirements have been implemented.

Commit: https://github.com/johneastman/circles/commit/0ce2b51904d97320b2ba18b3f0ec6ee36f41c622