* Headers/gnustep/base/objc-gnu2next.h: Remove simple mappings for
class_get_class_method they cannot work due to different
parameter expectations. Added mapping from NeXT->GNU runtime.
The other way does not work. Added simple mapping for internal
flush function __objc_update_dispatch_table_for_class and
_objc_flush_caches.
* Headers/gnustep/base/GSObjCRuntime.h/m:
Added typedef for GSMethod.
(GSGetInstanceMethod): New function.
(GSGetClassMethod): Ditto.
(GSGetInstanceMethodNotInherited): Ditto.
(GSGetClassMethodNotInherited): Ditto.
(GSFlushMethodCacheForClass): Ditto.
(flush_method_cache_for_class): Removed function which is replaced
by GSFlushMethodCacheForClass.
(GSObjCGetMethod): Removed function which is replaced by
GSGetInstanceMethod and GSGetClassMethod.
(GSObjCReplaceMethod): Removed function.