Add tests for calling sin and cos on very small inputs.
Fix sinh (and complex sin/cos) for small inputs
Fix the test case so it passes on all hardware.

The fix is to test that the imaginary part is nonzero,
not that it is exactly 1e-100.
In some software / hardware combos,
it seems to return 1.0000000000000001e-100.
Merge pull request #247 from pavpanchekha/complex-trig-accuracy

Accuracy of sinh and complex cos/sin