box-layout: Remove the allocations hash table
box-layout: Remove the allocations hash table

The BoxLayout uses a HashTable to map the latest stable allocation of
each child, in order to use that as the initial value during an
animation; this in spite of already having a perfectly valid per-child
storage as part of the layout manager: ClutterBoxChild.

The last stable allocation should be stored inside the ClutterBoxChild
instead of having it in the private data for ClutterBoxLayout. The
access remains O(1), since there is a 1:1 mapping between child and
BoxChild instances, but we save a little bit of memory and we avoid
keeping aroud allocations for old children.

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