Fixing knockback & movement.

• Adjusting the knockback to be reasonable level.
• Rewrite movement code to use acceleration.
• Adjusted speed, mass, and linear drag of the prefabs.
• Moved TryMove() down to Character.
• Made character death remove the object from the world by default.
• Created some starting code for the ability system (Not working yet, please don't touch)

approved this merge request

merged

mentioned in commit 89b76a80