Improve Scene Graph - Simple Material example documentation.

Change-Id: I5b77f7590c9f2cea9305014b8a9d4ab3a387eaa3
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Fix alignment exception in newCallContext on ARM

CallContext::locals was not at multiple of 8, which caused
an alignment exception on ARM. Size for the context is
also increased.

Change-Id: I136418f89945cd3fec74463659107c6dab7cad0a
Reviewed-by: aavit <eirik.aavitsland@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Avoid renderlist rebuilds in the scene graph renderer.

Transform, material, opacity and geometry changes all used to trigger
full rebuilds, which meant that very little geometry could be retained
between frames. For instance, a rotating spinner on top of a gridview
this would cause a full rebuild where nothing is retained.

This change introduces new concept to the renderer: partial rebuilding
based on render order ranges. Since the render order of nodes is
strictly defined by their position in the tree and nothing else, we
should use that for the majority of rebuilds. When a change comes in
for a node, we invalidate its batch and all batches which it has
overlapping render orders with.

Render order rebuilds only happen when nodes are added and removed.

Change-Id: Ib4cb284164892b409e3fff5c492a54d60a5de2d7
Reviewed-by: Michael Brasser <michael.brasser@live.com>