TST: Silence some warning that turns up on OpenBSD.

On OpenBSD with gcc-4.2 log1p(nan) raises an invalid value warning.
This PR disables both 'divide' and 'invalid' for the log1p tests.

Closes #5017.
BUG: Fix np.insert for inserting a single item into a structured array

Note that there are some object array special cases because of allowing
multiple inserts. `np.array(..., dtype=object)` is not always clear.
Merge pull request #5022 from seberg/structured-insert

BUG: Fix np.insert for inserting a single item into a structured array
Merge pull request #5020 from charris/disable-some-test-warnings

TST: Silence some warning that turns up on OpenBSD.
TST: join fft threads before getting values

avoids timeouts on slow machines
Merge pull request #5035 from juliantaylor/fft-test

TST: join fft threads before getting values
TST: skip clongdouble alignment checks on 32 bit arches

turns out not only sparc is borked, skip the checks on all 32 bit arches
with too large clongdouble alignments until we have an aligned
allocator.
Merge pull request #5040 from juliantaylor/align-backport

TST: skip clongdouble alignment checks on 32 bit arches for 1.9
BUG: fix array_almost_equal for array subclasses

introduced in gh-4105/ab04e1ae0e8eca717bc7e42f3b0a60c9ff764289
Merge pull request #5048 from juliantaylor/subclass-test-fix

BUG: fix array_almost_equal for array subclasses
TST: accept small error in threaded random test

freebsd and windows change x87 precision mode (fctrl bit 8 and 9) from
extended to double in child threads so the random numbers cannot be
exactly the same from master and child threads.
see gh-4909
Merge pull request #5051 from juliantaylor/thread-test-fix

TST: accept small error in threaded random test
DOC: sync release notes with 1.8 branch
DOC: fix missing space in percentile doc
REL: Release 1.9.0