Support NSSecureCoding in AFURLResponseSerialization
Support CGFLOAT_IS_DOUBLE  in AFImageResponseSerializer
[AFHTTPResponseSerializer] Use copy to ensure immutable types
Replace all uses of NSCoding to NSSecureCoding
Merge pull request #2049 from kylef/securecoding

Support NSSecureCoding and CGFLOAT_IS_DOUBLE with response serialisers