UI/ polish

I have created a main menu for back line with a title, start game button which will switch scene to the backline game a level button to choose the level of difficulty and a quit button.

within the game if a try is score a try! Panel is triggered and and comes up as an overlay with a title of Try! and three buttons on the screen retry, main menu and quit all these buttons are pretty self explanatory

if the player with the ball or the ball is passed out of bounds of the field or the player with the ball is tackled the game over panel overlays the game with a game over title and the same three buttons of retry, main menu and quit.