Fixed Camera and other updates

Camera is fixed! I think only one person commented on this issue, but it has been driving me crazy that lower levels could not be seen after jumping onto a higher level. Part of the reason is that I decided I wanted the camera to be 150 pixels above the character's head instead of at the exact same level as the character so half the screen would not be underground. I went through way more algebra than I should have to fix this, but I have it working so that even at the highest point, you can still see ground level. Someday I hope to make a tutorial devlog for other people using Gdevelop who might have had the same problem.

Anyway, full list of updates:

• The cameras! :)
• A score for each level based on how many ghosts you absorb.
• An easter egg that can be discovered if you get a perfect score on each level.
• Added a couple more ghosts and extra water sources in levels 2 & 3.
• Fixed glitch on level two where you can go inside the wall when starting the level.
• Added music to the menu.
• Added a jump sound effect at the suggestion streamer of RonTheArtist. I was having a hard time finding one I liked, so I ended up making one in Jfxr that I and decided to share here, in case it fits anyone else's project: https://opengameart.org/content/slime-jump-effect