Game in 16:9 and some bonuses

Something I had delayed for a loooong time, and I finally found the courage to work on it. 

From the start the game was in 4:3 format, because it was a simple prototype at the type and I hadn't done much research. After looking through various solutions, I decided to forgo adaptable layout size as it seemed to imply too many things possibly breaking, and decided to go to the 16:9 format which seems more adapted nowadays. It took some redrawing of the backgrounds and rearranging of a lot of levels, menus, ui, and so on. That makes the levels after world 1 even more broken than before. I will get to fixing them in due time, after I've ascertained the new aspect ratio works properly.

Aside from this : 

-added some sound effects (jump, dash, chest fall, death, enemy death). They're pretty quiet right now, let me know your thoughts on these.

-added a new crab enemy which gets its own level, and rearranged the levels a little. 

-polished the first boss visuals & level.