BYOND Parity Renderer

[amylizzle]

Attempts to implement a parity matching renderer, using https://secure.byond.com/docs/ref/#/{notes}/renderer as a reference.

• Appearance Flags
• Underlays
• Overlays
• Recursive Under/overlays
• Blend modes
• Color
• Alpha
• Transforms
• Filters
• KT groups
• Planes
• Render source/render target
• Plane master
• Screen
• Special plane values
• Layers
• Invisibility

Fixes #170
Fixes #199
Fixes #295
Fixes #196
Fixes #1061

Renders unmodified paradise! (You still need 64bit rustg)
OpenDream:

BYOND

Things still to do that someone else can do (or more likely, something I can do later):

• client.images (needed for character sprite drawing)
• Visual contents
• Maptext
• Particles
• atom.appearance (this is why terminals don't have screens and some overlays don't work)

[ike709]

Particles

You should probably hold off on particles until RT implements their new effect system.

[amylizzle]

Note: I don't actually intend to implement everything on the list. I am gonna have a fair crack at some of it though.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.