Fixed Bug with Jumping

Changed the way that the jump works.

Before there was a bug where you could jump infinitelly if you hit the ceiling. Also, you could use two jumps in the air if you didn't use your first one to get off the ground. This was because I was enabling the ground jump when the character vertical speed was 0, but not disabling it.

Now I fixed it, so  the ground jump is only enabled WHILE the character is standing on a block. This makes impossible to use some shortcuts I found before, like one on level 5. I also had to modify level 10 a little cause it got impossible.

I didn't made changes on the levels aside from level 10 and 9 (because of the level 10), so the difficulty is still pretty hard.

Anyway, wish you a nice weekend!