feat: OmitEmpty() omits zero-length slices and maps

feat: Hide[T]() completely omits fields of the given type

fix: show type when value is within "any"

eg.

    []any{int64(1)}

Without this, numeric types would have the same representation even if
the types differed.

Also use `any` rather than `interface {}`.

fix: use stdlib IsZero()

fix: panic on Interface()

Replaces #13