Quality of life bugs

[saulshanabrook]

Keeping this issues open with a list of running quality of life changes observed when watching someone else try out getting started.

• i64 is not capitalized. It probably should be
• Remove need to subclass from Expr, instead move != to funciton
• Currently cannot define late binding definitions in classes that depend on later classes. Maybe should add this
• Add a better error for when you forget type annotations
• Use numpy like array for the opening tutorial - Maybe instead do AST eval
• Instead of egraph.register and egraph.class_ use egraph instead to reduce noise.
• Remove automatic generation of py objects in graph.