draw board

[daburch]

• Changed App to remove the default react header and instead draw a simple checker board.
• Added css for board and squares
• created board and square components

Board:

• when a board component is initialized, componentDidMount() is called, like a constructor.
• board mount builds an array of 64 strings using a double for loop and sets the color of each square here.
• the board render will create a square component for each item in the array created during mounting

Square:

• creates a simple div with the css class needed for the color set on it

[daburch]

Sticking with current colors for now. New versions can be added later if wanted.