Fix Slime behavior and animations

[Luis-Tavares]

Currently, the Slime is constantly jumping, but its actual behavior should be:

• While isn't moving, the Idle animation should be playing.
  • A second before the jump, it should play the Pre animation so the player can predict its attack.
  • After this, the Slime should Jump, and the jump duration should match with the animation duration.

[Luis-Tavares]

If you prefer, I can change the Jump animation to multiple animations so we can have better control of the timing. For example, Rising, Falling, and Collide animations instead of Jump.

[herux]

yes, that's better

[Luis-Tavares]

I've updated the animations. Now, instead of a single jump animation, there are 3:

• The Jump that plays when the slime is rising.
• The Fall that plays when the slime starts falling down.
• The Collide that plays when the slime shocks on the floor.

PS: Those aren't looped animations, so it must play only once and stays on the last frame until the next animation plays.