Laurent series of coth around %i*%pi

taylor(coth(x), x, %i*%pi, 0) gives an error: `quotient' by `zero'.

Also, taylor(coth(x), x, %i*%pi, -1) might also be expected to return the 1/(x - %i*%pi) term instead of 0.

Cf. Maxima list, March 31st, 2007: "Using taylor() for Laurent series".