Random sampling mygrad.random

[rsokl]

These no-backprop functions should simply wrap the corresponding numpy functions, but return tensors. constant=False should be included as a default argument. Simply write a wrapper that converts these numpy functions to mygrad ones (returning tensors). The return statement in the docstring should be updated as such.

mygrad/random/funcs.py

• rand
• randn
• randint
• random_integers
• random_sample
• random
• ranf
• sample

[petarmhg]

Closed by #257.