* Fixed the description of the return value of argrelmin, argrelmax,
argrelextrema and _boolrelextream.
* Fixed the example in the docstring of _boolrelextream.
* Added examples to the docstrings of argrelmin, argrelmax and
* Added more tests for argrelmin and argrelmax.
* Removed some commented-out code and unused imports from test_peak_finding.py
along with an unused variable (num_peaks) in _gen_gaussians().
* Removed an argument ('order=2') from the signature of
TestArgrel.test_higher_order() in test_peak_finding.py.
* Removed unnecessary special check in argrelextrema that incorrectly
returned a length 2 tuple when there were no relative extrema,
regardless of the dimension of the input. Fixes gh-2832.
* Several more minor tweaks.