Implement functions from np.random

[prasunanand]

WIP

[prasunanand]

Currently I get following error:

(uarray) prasun@prasun-xps:~/dev/labs/unumpy$ pytest -vv -x
============================= test session starts ==============================
platform linux -- Python 3.7.5, pytest-5.3.2, py-1.8.0, pluggy-0.13.1 -- /home/prasun/anaconda3/envs/uarray/bin/python
cachedir: .pytest_cache
rootdir: /home/prasun/dev/labs/unumpy, inifile: pytest.ini, testpaths: unumpy
plugins: mypy-0.4.2, flake8-1.0.4, cov-2.8.1, black-0.3.7
collected 25 items / 1 error / 24 selected                                     

==================================== ERRORS ====================================
_________________ ERROR collecting unumpy/tests/test_numpy.py __________________
unumpy/tests/test_numpy.py:289: in <module>
    (np.random.rand, (1, 2), {}),
E   AttributeError: 'uarray._Function' object has no attribute 'rand'

[hameerabbasi]

A lot of these don't take in array_like arguments at all. Most of them (not all) should just be return () paired with identity_argreplacer.

Try to be a bit more careful with your dispatcher and arg-replacer. The dispatcher extracts array_like arguments and dtypes.

[hameerabbasi]

This should be replaced by checking the __module__ of the method.

[prasunanand]

Not sure about this :/

[hameerabbasi]

You have to check method.__module__. It will be different depending on the submodule that the method is in.

For simplicity, you can also move everything in _multimethods.py to __init__.py.

[hameerabbasi]

Superceded by #73.

[joaosferreira]

Might take over this eventually if that's okay.