World Game Update v0.0.0.13

Another update to World Game!

• Added generated icons on inventory slots that contain a block.
• Added Icon of the currently selected block in the Player's HUD.
• Replaced "world_game:punch" sound with "world_game:punch_fail" sound when trying to attack NPC with iframes.
• Redone Ground Friction so it won't depend on Framerate.
• Slight adjustments to footstep sound pacing.
• The Player can no longer sprint backward.
• Footstep SFX will now also play when the player or other entities land.
• Slots will no longer change color when selecting them.
• Fixed bug where moving diagonally doubles movement speed.
• Fixed bug where the wrong footstep sound plays when walking at the edge of a block.
• Fixed bug where jumping relies on framerate.
• [back-end] Fixed Update will now run 60 times per second instead of 50.
• [back-end] Reworked item slots to be still functional without inventory.
• [back-end] LivingEntity class will now detect and store the block type they're standing on.
• [back-end] All Entities now have overridable FixedUpdate() method.
• [back-end] Added a method to directly set a specific itemstack inside the inventory.

[back-end] = Features not added to the game, but is inside the game's code.

Please if you find any bugs, report it. Have Fun! :)