initial commit: background sprites and enemy spawning
add player object and movement control
handle collisions
missile launching and collision
larger background sprites and faster movement; add beetle sprite
added dung sprites for enemies
reduce background sprite size again; also reduce speeds
add laser sprite
dung explosions; welcome screen with logo and loading bar
add glowing logo to welcome screen
help screen and game title text on home screen background img
lighten up background color
Merge branch 'master' into gh-pages