Adding a public interface for validating type codes

[ZeroIntensity]

Feature description

The type code system used in _view for handling type validation works quite well, but there's no good API for accessing it from Python. The user should be able to do manual type validation if they feel like it.

Feature example API

from view import compile_type
from typing import TypedDict

class Test(TypedDict):
    a: str

tp = compile_type(Test)
tp.validate({"a": "b"})  # OK
tp.check_type({})  # False

Anything else?

This will delay #30, again.