ENH: Avoiding conversion of integer to NumPy Scalar.
There is a bottleneck in scalar operations, when trying to extract the
underlying C value from a Python integer/float. I have avoid conversion
for know integer type but extracting its value.
Extracting longlong value without converting it to NyType
Moved int test cases to pr#3592
Added PyInt_CheckExact for python < 3 and error check for PyLong_AsLong
Replaced PyInt_As_Long with PyInt_AsLong and  errorchecking
Check for error value by PyLong_AsUnsignedLong as (unsigned long)-1