Support complex (float/double) types in array.array and memoryview

[skirpichev]

Currently, we have support for this in the struct and the ctypes modules, working rather with heterogeneous binary data. Lets add these types to the array module as well ('F'/'D' type codes).

I think this feature can be available unconditionally, like for the struct module.

[serhiy-storchaka]

If this is supported in the struct module, there is no reasons to not support it in array.array and memoryview.