Also cleaned up the current render target buffer binding code, added more debug logging as well.

Change-Id: I6e286f7c9714f3c54353098f0447f5b719a68d58
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

Change-Id: Ib1ada2b821c574333f726b7228c430876a49856a
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

Check for ES using isOpenGLES() instead. The method was introduced in
Qt 5.3.

Change-Id: Id21659fcaa1e1854c07df38147ad666207778cb2
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

Change-Id: Id56053764835e13bf475d76230ea4a6c356161ca
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

QQmlPropertyMap as baseclass doesn't work without additional work, it has been now removed as baseclass from QtCanvas3D for now.
TextureLoader has been removed in favor of TextureImageFactory as that allows easier porting of WebGL based JavaScript code to QtCanvas3D.

Change-Id: I6fb374fd012d7569b9f173b08f4a6f21dcd83abe
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

All JavaScript visible objects are now based on QQmlPropertyMap so that libraries and other users can add dynamic properties to the objects like they do in many cases. Also fixed textured cube example to respect devicePixelRatio.

Change-Id: I71a8d8e32e2d856dc1c97f498c9a34b3858ab6a9
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>

Change-Id: Ief2c39fd4ec0d985ed8184e33bde0190b8b338cf
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>