Removed U-mode interrupts, as they are no longer in the standard
Transition from Vector unions to Option<fn>. Both are equivalent, as Option<fn> exploits a niche optimization that uses 0usize to represent None. However, using Options is more idiomatic than Unions
Added a mechanism to deal with exceptions that is similar to how we treat interrupts. Now, it allow us to define custom exception handlers for standard exception sources.
This PR consists of three major contributions:
Vectorunions toOption<fn>. Both are equivalent, asOption<fn>exploits a niche optimization that uses0usizeto representNone. However, usingOptions is more idiomatic thanUnions