Added new game button, added tabs, altered supporting code

I added a New Game button to the right panel and altered Stephen's code some. Using draw_grid by itself didn't work, so I had to capture all the logic for the game and redrawing the board into a function called newGame. Also created an initPlayer function to reset the display to correctly show Player1 and toggle correctly from there.

Added some constants to the connect.js file: PLAYER_ONE, PLAYER_TWO, NUM_ROWS, NUM_COLS.

Added tab functionality. Just the basics, will need to be spruced up. I added tabs.css to support this feature.

connect.css has no actual changes.