Evercore v2.3.0

• Implemented Meep's Smooth Springs, saving sprite space and improving visuals.
• Added sideways spring functionality, with support for being placed on crumble blocks.
• Added tile-based semisolid platforms (aka "jumpthroughs") as a default object.

These are features that a lot of mods implement anyways, so they're now included by default.

• Updated layering system to be more powerful, with no limitations on the number of layers. (thanks meep and gonen!)
• The layer variable is now stored per-object instead of per-type, allowing objects to change draw layering during runtime.
• Reformatted and reorganized cartridge. In the PICO-8 editor the code is now sorted into tabs.
• Updated example levels
• Updated README
• Fixed typo (thanks snek lol)