New Main Menu, Ice Blocks, Occlusions, and Ground Cover

Replaced the entire main menu system with a whole new one
Added support for having multiple save files and switching between them in the main menu (deletion/duplication coming soon)
Added support for template level files which restrict resizing of the level and deletion of certain walls
Added a Ground Cover that can cover things on the ground and disable their effects. Added a broom pickup that can be used to sweep away Ground Cover entities
Added Ice Block entities that can hold things and be pushed around
Added a Freeze Rod powerup that allows you to throw projectiles that freeze things
Added freezing and melting Effect Pads
Added a cloud looking Occlusion entity that hides things and doesn't allow enemies to pass through it but dissipates when the player steps into the space
Made lasers change colors when passing over painter entities
Started working on a shuriken throwable pickup item (unfinished)
Started working on a shield pickup item (unfinished)
Replaced 2 of the levels in the demo showcase
Added a short tutorial level
Added some new decorations and a wall type used for the king's palace at the beginning of the tutorial

Added some preset keybinding options that allow you to play the game with WASD or IJKL. Changed some other things in the settings menu
Changed the icon for puzzles to be a jigsaw puzzle piece
Changed the way we allocate entities in level structures
Added the ability to do debug output from mylib and get line numbers from the debug outputin the platform layer
Changed the way the reset button works when inside a puzzle area. Changed the wording of the reset options on the in-game menu
Fixed a save game world location deserialization bug
Moved the demo showcase level into a new LevelType so it shows up properly in the new main menu. This will cause progress on the showcase to be lost unfortunately given the way the current save game works