Refactored cloud rendering to allow multiple clouds
Restored full cloud opacity
[#1] Crash buds on collisions
Refactored background drawing

Better rendering for collisions
'Stop' button added
[#1] Collide against the bounds of the level
[#2] Add goal to level
Show different leaves colors if over goal cells
Refactored action application
Use action constants
[#2] Added winning and losing verifications
Added a cloud and reordered layers
Made goal cells transparent and changed colors
First work on resizing
Added SVG icons
Homogeneize svg icons, first export to bitmap
Split rendering function into several parts
Added asynchronous image loading
Added button drawing
Added count on buttons