Enhanced menu

Start + Exit
major update

changed resolution
added icons
game status
android back button
play scene logic + less logic in game layer and bg
winsize global var
bullet speed
version 0.4.3

added utilities to load and save stats and global settings and also
play sounds if sounds are on
sound on/off
statistics
bug fix in bullet reachedBounds
Enemy cleanup
game layer can remove all objects
removed high score from main menu
endgame is now generic (for back button and game over)
enemies and bullets are removed from screen and stop updating on game
over
status layer doesn’t hold points var anymore