Starting to move towards QJSValue use

Starting to replace QObject pointers with QJSValue that allows dynamic
properties to be added to the the returned objects from QCanvas3D API.
This makes the implementation more compatible with WebGL code out there.

All uniform??va functions made internal, uniform??v functions now accept
QJSValue as input and dynamically detect the parameter type.
Examples updated accordingly.

Buffer3D, Program3D, Shader3D and UniformLocation3D types now changed
to use QJSValue.

Change-Id: I1670d5efa5aa829c89169143b685e4b52b402b77
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>