Bug fixes + a few new items

- added water
- added tooltip to the UI to indicate the currently equipped item
- particle effects for liquids are more customizable
- fixed items not fully deleting when used (i.e. potions)
- improved inventory handling when calling deleteAllObjects, there is
now an option to ignore any items in the inventory
- fixed some projectiles having an inverted knockback effect
- fixed AI not following player while jumping
- fixed player sinking into the ends of platforms
- projectiles disappear when going through certain liquids
- grappling hook is more accurate
- player is not affected by gravity when being pulled by grappling hook
- only one hook can be shot at a time
- if selected slot is full, items are added to the next available slot
- added chests (still buggy)
- crafting menu items are properly aligned
- separated player's range hitbox into line of sight and range
- added a few demo levels
- the Timer class is now automated, any objects that create an instance
of the Timer class do not have to manually update it unless needed
- fixed bug where items do not delete after being used in a crafting
recipe
- added ammo counts to the hotbar (setting the ammo count to -1 will
give the item infinite ammo and the number will not be rendered in the
hotbar)