ObjC: renamed subproject from objcpp to ObjC

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
ObjC: added symbolic link so that we can test-run by ./objc

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
ObjC: added -d option to usage messame

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>