added a start button on pageload, when the user clicks start it runs
snakeInit and the start button reappears after the snake is deleted
added start button image, added code to delete the EVentListener after
SnakeInit is called
Merge branch 'master' into mainmenu

Conflicts:
	Snake.html
Merge pull request #32 from jasontowens/mainmenu

Mainmenu
Merge branch 'master' into levels2

Conflicts:
	Snake.html
Just some spacing changes. i.e. readibility.