Code for these two classes was already present but it was commented
out or left outside of the build system because it didn't even
compile. I've brought it back and made it compile, but it has no use
yet. The goal is using it to preserve 3D transformations.

At scene3dcontext.cxx I removed the text chunks found in the middle
of the source and corrected some mistakes; I also modified the
conversion of "fov" attribute.

At shape3dproperties.hxx I removed all the struct members because
they seemed to have been copied&pasted from another file, and added
only those members that made sense. Removed useless function
definitions.

Change-Id: I2c00ea638e1a4fb1a3820bc4c322488296d3e6d7