Typemaker 1.1 Rebased Redux

[ike709]

Essentially just revives https://github.com/OpenDreamProject/OpenDream/pull/2208 with some key differences:

• No merge conflicts (yet)
• Does not do as params at all. This PR is large enough as-is and I don't want to figure out the passing around procParameters mess
• Tweaked the error message for typemaker
• Fixed the morbillion formatting warnings
• Fixed an NRE on compiling testgame
• Fixed some other stuff that I forgot about between committing and writing this desc
• Support astype() in typemaker
• Handle ImplicitNullType for proc args

Note that passing the --skip-anything-typecheck compiler option is still strongly recommended for trying to actually use typemaker.

Also don't forget to elevate the typemaker pragmas to warnings/errors for this to actually do anything.

Future PR things:

• alist() support
• More unit tests
• Revisit as params from the original PR