script: Take a copy of property nodes
script: Take a copy of property nodes

Instead of counting on a JsonNode pointer to survive we should take
a copy. This allows keeping unresolved properties across different
ClutterScript passes.

heysion/clutter-clone,jigpu/clutter,rkudiyarov/clutter_osx,dlespiau/clutter,collects/clutter,djdeath/clutter-multithreaded,collects/clutter,djdeath/clutter-android,Distrotech/clutter,kerrickstaley/clutter-vala,djdeath/clutter,ebassi/clutter,dlespiau/clutter,collects/clutter,djdeath/clutter,djdeath/clutter-multithreaded,spatulasnout/clutter,spatulasnout/clutter,heysion/clutter-clone,djdeath/clutter,spatulasnout/clutter,djdeath/clutter,djdeath/clutter,GNOME/clutter,djdeath/clutter-multithreaded,djdeath/clutter-android,collects/clutter,nobled/clutter,GNOME/clutter,Distrotech/clutter,djdeath/clutter-android,jigpu/clutter,kerrickstaley/clutter-vala,jigpu/clutter,GNOME/clutter,Distrotech/clutter,Distrotech/clutter,ebassi/clutter,kerrickstaley/clutter-vala,heysion/clutter-clone,collects/clutter,kerrickstaley/clutter-vala,dlespiau/clutter,rkudiyarov/clutter_osx,djdeath/clutter,heysion/clutter-clone,rkudiyarov/clutter_osx,nobled/clutter,jigpu/clutter,spatulasnout/clutter,heysion/clutter-clone,GNOME/clutter,Distrotech/clutter,ebassi/clutter,djdeath/clutter-multithreaded,djdeath/clutter-android,djdeath/clutter-android,spatulasnout/clutter,nobled/clutter,Distrotech/clutter,jigpu/clutter,rkudiyarov/clutter_osx,ebassi/clutter,jigpu/clutter,ebassi/clutter,GNOME/clutter