beta-4.3: New health texture.

For some reason, the improvements of beta-4.1 and beta-4.2 might have not been properly added. So, here are the 2 updates smushed together into beta-4.3 to make sure the improvements are added.

Improvements

• Removed the voice in Level 5; it said the same phrases as the voice in Level 4.
• Added a texture for the health power-up: Heart 16*16 by Nicole Marie T, licensed under CC BY 3.0.
• Changed the colour of the text when healed from blue to green.
• New screenshots on itch.io.