Added Healthbar-Script + Heart-Images to use.
Atm it's using hearts which are drawn at the upper left corner and exchanged with empty heart containers if damaged.

HealthBar.cs has to be added to the Player & textures have to be added.

Changed Raindrop.cs so that if raindrops collide with player, the health gets reduced by 1. (See bug below)

!!! Bug !!!
Still have a "bug":
Health gets randomly reduced by 2 instead of 1 if hit by raindrops. Mostly happens if player stands right in front of raincloud.
Maybe "double collision" (???) with player -> -2 health instead of -1.