BUG: Bug in inplace operations with column sub-selections on the lhs (GH8511)
Merge pull request #8520 from jreback/indexing

BUG: Bug in inplace operations with column sub-selections on the lhs (GH8511)
BUG: Suppress FutureWarning generated by NumPy when comparing object arrays containing NaN for equality.
Avoid FutureWarning by implementing equality check in Cython.