Bug 1349 - Using the anchor point to set the scale center is messy
The branch adds an extra center point for scaling which can be used
for example to set a scale about the center without affecting the
position of the actor.
The scale center can be specified as a unit offset from the origin or
as a gravity. If specified as a gravity it will be stored as a
fraction of the actor's size so that the position will track when the
actor changes size.
The anchor point and rotation centers have been modified so they can
be set with a gravity in the same way. However, only the Z rotation
exposes a property to set using a gravity because the other two
require a Z coordinate which doesn't make sense to interpret as a
fraction of the actor's width or height.
Conflicts:
clutter/clutter-actor.c
3e68b23ea8