Fix up datetime argmin/argmax/min/max
Fix up datetime argmin/argmax/min/max

stuartarchibald/numba,cpcloud/numba,sklam/numba,gmarkall/numba,stonebig/numba,gmarkall/numba,stonebig/numba,sklam/numba,numba/numba,seibert/numba,stuartarchibald/numba,IntelLabs/numba,numba/numba,seibert/numba,numba/numba,stuartarchibald/numba,cpcloud/numba,sklam/numba,seibert/numba,cpcloud/numba,cpcloud/numba,stonebig/numba,stuartarchibald/numba,seibert/numba,gmarkall/numba,cpcloud/numba,stuartarchibald/numba,IntelLabs/numba,gmarkall/numba,numba/numba,seibert/numba,sklam/numba,numba/numba,sklam/numba,stonebig/numba,IntelLabs/numba,IntelLabs/numba,IntelLabs/numba,gmarkall/numba,stonebig/numba