Renderer RenderThread reversal

RendererAspect now creates the Renderer object directly. In turn the Renderer
privately creates the RenderThread. This is more logical and makes for an
easier understanding of the code. The behavior is otherwise unchanged.

Change-Id: Ie6a2caa11cf9d01c87972a9b5e3296752deaca65
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Ground work to have a proper shutdown

QAspectEngine shutdown invokes QAspectManager quit which will stop the
QAspectThread. Prior to exiting, the QAspectThread calls QAspectManager
shutdown which cleans up all aspects and deletes them.
Renderer stops the RenderThread when cleanup is called and properly deletes
the QGraphicContext and the RenderThread.
Note: Everything is called as it should. However it always ends up in a
segfault caused by the QFont::cleanup when the QThreadStorage of the main
thread GuiApplication is destroyed. I've not been able to find the cause of
that.

Change-Id: I3b7baa843af4d0418b5d04e6d1cda88b962ded7f
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>