add thyme dependency
Introduce expm1 and log1p to Trig[A].

These methods are needed to make generic programming safe for
floating-point values.

Right now, Complex[A]#log1p and Complex[A]#expm1 use naive
implementations for these. Arguably, if a complex number is real
(i.e. has no imaginary part) we should instead use Trig[A]#log1p
and Trig[A]#expm1.