API: raise a TypeError on invalid comparison ops on Series (e.g. integer/datetime) GH4968

[jreback]

closes #4968

[cpcloud]

Just as an FYI as to why this PR is working:

1. We have __eq__ using operator.eq which will return the result of calling an object's overridden tp_richcompare method or a bool (if the former lhs and rhs methods return NotImplemented). This is because operator.eq compares pointers if both the left-hand-side and right-hand-side methods return NotImplemented. In this case, ndarray.__eq__ is return NotImplemented for both the left and right hand side. Python then proceeds to compare object pointers.
2. The wrapper function receives a bool from na_op. wrapper constructs the result with the left-hand-side's index which will fill the result with a single value if it's passed

[jreback]

@jtratner @cpcloud ok to merge then....?

[cpcloud]

hold on 1 sec want to try something

[cpcloud]

yep okay, good 2 go