Add image resizing and rotation to NS port

Add image resizing and rotation to NS port

* lisp/image.el (image--get-imagemagick-and-warn): Bypass imagemagick
check when using NS.
* src/nsimage.m (ns_load_image): Add rotation and resizing
functionality. Move the getMetaData call to before the resize/rotation
so it returns correct metadata.
(EmacsImage::setSizeFromSpec, EmacsImage::rotate): New functions.
* src/nsterm.h (EmacsImage): Add new function prototypes.
(NSCompositingOperationCopy): Add define to older equivalent for
GNUstep and pre-10.12 macOS.
* configure.ac: Don't use libjpeg on Cocoa.