gdal_array.NumericTypeCodeToGDALTypeCode does not accept numpy dtype arguments (patch)

[lpinner]

Patch to enable checks against numpy dtypes as well as types attached.

Why...? Not all numpy types are created equal! Consider this (on Windows, works as expected on Linux):

import numpy as np, numexpr as ne
from osgeo import gdal_array

a = np.array([1], np.int32)
b = ne.evaluate('a')

print 'dtypes:',a.dtype,b.dtype
print 'types:',a.dtype.type,b.dtype.type

print 'Compare dtypes:', a.dtype==b.dtype
print 'Compare dtype.types:', a.dtype.type==b.dtype.type
print 'Compare a.dtype to np.int32:', a.dtype==np.int32
print 'Compare b.dtype to np.int32:', b.dtype==np.int32

print 'NumericTypeCodeToGDALTypeCode(a.dtype.type):',repr(gdal_array.NumericTypeCodeToGDALTypeCode(a.dtype.type))
print 'NumericTypeCodeToGDALTypeCode(b.dtype.type):',repr(gdal_array.NumericTypeCodeToGDALTypeCode(b.dtype.type))

This outputs:

dtypes: int32 int32
types: <type 'numpy.int32'> <type 'numpy.int32'>
Compare dtypes (expected output True): True
Compare types (expected output True): False
Compare b.dtype.type to np.int32 (expected output True): True
Compare b.dtype.type to np.int32 (expected output True): False
b.dtype.type is actually a np.intc: True
NumericTypeCodeToGDALTypeCode(a.dtype.type): 5
NumericTypeCodeToGDALTypeCode(b.dtype.type): None

With the patch applied, I can pass b.dtype:

print gdal_array.NumericTypeCodeToGDALTypeCode(b.dtype)
5