adderall.dsl: Add a (buggy) condⁱ implementation

This adds a condⁱ implementation that satisfies some of the tests from
chapter 6, but fails others (disabled test added too). The
implementation is known wrong, it does not interleave. But it's a start
for further developments.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
tests: Added more disabled tests from chapter 6 of TRS

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
adderall.dsl: Implement a few bit/ and num/ functions

Implements a number of bit/ and num/ functions from The Reasoned Schemer
chapter 7.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>