Version 0.2 : Quick fix

Update containing  some  changes and fixes.

Notable changes:

• Add new idle animation for the player character
• Correcly rescale the HUD according to the screen size
• Update the scoring system : you can now earn points by killing lymphocytes
• Remove the collision between antibodies (enemy bullets) and virions (player bullets)

Bug fixes :

• Fix bug where the player could infect several cells at a time
• Fix bug where super lymphocytes would spawn at the very start of the game if you restarted it
• Fix bug where you could be healed when already dead
• Fix bug where the moving animation of the player didn't show when going up left or down left