pyuvdata/src/miriad_wrap.h: fix for numpy inputs on Python 3
pyuvdata/src/miriad_wrap.h: fix for numpy inputs on Python 3

In Python 3, the Numpy integer types no longer inherit from the `int` type,
which broke our (helpful) ability to accept types like np.int32 as integers.
Work around this in the C by also checking for numbers via `PyIndex_Check()`.

HERA-Team/pyuvdata,HERA-Team/pyuvdata,HERA-Team/pyuvdata,HERA-Team/pyuvdata