BUG: NPY_LOGE2 is log(2)
BUG: Test aginst +/-TANH_HUGE

This is a bug introduced when adapting the FreeBSD implementation. Since
they play some games extracting parts of the double and comparing them
as unsigned ints and we don't. We don't since that doesn't generalize to
float, and long double as we do in npy_math_complex.c.src
TST: check for tanh(1000+0j) == 1 + 0j etc.

This is a test for the fix for gh-2321.
BUG: Fix up some corner cases in npy_cexp

The failing c99 annex G values for cexp were:
cexp(Inf, -0) == (NAN, -0)
cexp(Inf, Inf) == (+-Inf, NAN) + raises FE_INVALID

The first returned (NAN, 0) and the second was correct but failed to
raise the invalid floating-point exception.
MAINT: remove debug print statement