DOC: Fixed incorrect assert_array_almost_equal_nulp documentation

The `max()` function previously used does not work with two array-like.
`maximum()` does, and is what is essentially used in the code
(`ref = nulp * np.spacing(np.where(ax > ay, ax, ay))`).

BUG: fix array_almost_equal for array subclasses

introduced in gh-4105/ab04e1ae0e8eca717bc7e42f3b0a60c9ff764289

documentation updates for 1.9

"Raise an assertion" was changed to "Raises an AssertionError" to clarify that
an exception named AssertionError will be raised.
Closes gh-4884

[ci skip]

merge master into 1.9 branch

Point release notes to doc/release/1.9.0-notes.rst
Set LOG_START to 'v1.8.1'
Set LOG_END to 'maintenance/1.9.x'
Set raise_warnings to "release" in NoseTester constructor.

This allows numpy 1.9 testing to be used with current scipy
without flooding the output with deprecation warnings.

The deprecation warnings are currently issued for both the
subtract and negative operators when used with booleans.