v2.1.0

@ishihara1989

This is the release of v2.1.0. See here for the complete list of solved issues and merged PRs.

New features

Add argpartition (#608)
Add window functions (#612, thanks @ishihara1989!)
- blackman, hamming, hanning
Support sparse.coo_matrix initialization with other types of sparse matrices (#626)
Line memory profiler using memory hook and traceback (#630)
Support dtype argument in random.randint (#706)
cuDNN grouped convolution (#721, thanks @anaruse!)

Performance improvements
- Optimize sparse.csc_matrix.__mul__ (#625)
- Cythonize memory hook (#728)
Support uint32 sampling up to 0xffffffff in random.RandomState.interval (#633)
Fix random.RandomState.seed to only accept integer types (#709)
Fix typo in IndexError error message (#683)
Fix interface for cuDNN find algorithm APIs (#664)

Fix OverflowError passing large integer to elementwise operation (#615)
Fix indexing zero-dimensional array with boolean mask (#645)
Setup Python’s builtin random state in testing.fix_random (#648)
Use v6 RNN API when using cuDNN7 to avoid incompatibility (#665, thanks @anaruse!)
Set arch option for NVRTC, as the option is neccessary on some GPUs (#696, thanks @grafi-tt!)
Fix memory pool for multi-threaded applications (#697)
Fix var and std to correctly handle ddof argument (#711, thanks @stevendbrown!)
Fix advanced indexing to not alter the indices (#723, thanks @yuyu2172!)

Fix a link in README.md to the contribution guide (#629)
Remove unrelated “see also” from testing.numpy_cupy_raises (#637, thanks @Hakuyume!)
Write note about environment variables for installation (#641)
Fix reference page of linalg (#651)
Fix doctest for Python 3.5 (#663)
Add intersphinx mapping to Chainer (#666)
Fix typo and heading in documentation (#667)
Update testing section in the contribution guide (#716)
Fix a link in README.md to the forum (#754, thanks @muupan!)
Fix incorrect heading “CuPy” instead of “NumPy” in license page (#674)

Use the latest Cython in Travis CI (#636)
Fix typo (#647, thanks @Hakuyume!)
Move to PyTest
- Move to PyTest (#659)
- Remove nose dependency in tests (#676)
- Use pytest-warnings to check deprecated warnings (#729)
Fix doctest for Python 3.5 (#663)
Allow filtering test cases by number of GPUs with CUPY_TEST_GPU_LIMIT environment variable (#677)
Ignore ComplexWarning in numpy.pad for NumPy 1.11 or older (#690)
Fix NumPy warning for bool and complex operations (#708)
Fix test of where to use different seeds for different arrays (#710)
Skip some dtypes in test_einsum (#740)
Skip some tests for old NumPy (#746)