Add demo files

app/src/main/res/drawable/green64.png

app/src/main/res/drawable/heart.png

app/src/main/res/drawable/help.png

app/src/main/res/drawable/home.png

app/src/main/res/drawable/ic_launcher_background.xml

app/src/main/res/drawable/invaderslogo.png

app/src/main/res/drawable/leftbutton.png

app/src/main/res/drawable/logobit.png

app/src/main/res/drawable/mute.png

app/src/main/res/drawable/play.png

app/src/main/res/drawable/playbutton.png

app/src/main/res/drawable/player.png

app/src/main/res/drawable/player2.png

app/src/main/res/drawable/player3.png

app/src/main/res/drawable/player4.png

app/src/main/res/drawable/red.png

app/src/main/res/drawable/red32.png

app/src/main/res/drawable/red64.png

app/src/main/res/drawable/replay.png

app/src/main/res/drawable/rightbutton.png