Remove print statements from Index
Remove __setstate__ and __getstate__ from MI + stub for __reduce__
Do better job marking where copies should/shouldnt be made
Add notes to index.pyx for clarity
Avoid issues with slicing and wrong comparisons for verify_integrity
Put ABCs last in core/common instance checks
switch view for values
Fix _fast_union
Replace Index.view(ndarray) with _values_no_copy
Short circuit PeriodIndex.asobject via ObjectIndex
Fix isin call to use _array_values() instead