add predicate (selfApp? TTerm), true for (x x) or (y y) or ...
add predicate (ω? TTerm) ("omega", with lower-case "o"): true for (λx.x x) or (λy.y y) or ...
add predicate (Ω? TTerm) ("Omega", with upper-case "O"): true for ((λx.x x) (λx.x x)) or ((λx.x x) (λy.y y)) or ...
implement betaReduce :: TTerm -> Maybe TTerm in lambda-style (almost pure); fix betaContract wrt Omega
comment out bogus diag in Base tests
add fn (Maybe-lift-in f), which expects a Maybe and if it's Some, passes the Some's value to f, returning whatever f returns (and None otherwise)
implement etaReduce and betaReduce in terms of Maybe-lift-in
refactor Substitution tests, to accomodate for lambda-style subst-seq
delete now obsolete MethodFixedPoint.pm6