Fixes for numpy 1.14.0 compatibility

- UPDATEIFCOPY is deprecated, replaced with similar (but not identical)
  WRITEBACKIFCOPY; trying to access the flag causes a deprecation
  warning under numpy 1.14, so just check the new flag there.
- Numpy `repr` formatting of floats changed in 1.14.0 to `[1., 2., 3.]`
  instead of the pre-1.14 `[ 1.,  2.,  3.]`.  Updated the tests to
  check for equality with the `repr(...)` value rather than the
  hard-coded (and now version-dependent) string representation.