draft release notes 1.6d20 to 1.7b1

[James W. W. <os...@jw...>]

I went through the CVS mailing list from Dec. 4 to now and made some 
notes for the 1.7b1 change notes.

Roger, do you expect to finish your view hints change before we do 
1.7b1?  If so, how would you describe it?

* Quesa is now compiled as C++, although the public API is still C.
* The code has been overhauled, taking advantage of C++ for better 
speed.
* memory storage objects can be duplicated.
* texture objects are correctly duplicated.
* when reading text 3DMF, references are handled correctly.
* mipmap textures are handled more correctly.
* The CodeWarrior project for the Geom Test sample has Windows targets.
* Minor improvements in the RayShade renderer.
* There is a new public API CENameElement_PeekData.
* textures are cached differently, to allow using a texture object with 
different texture shaders.
* fixed a bug in draw context pane positions in "metal" Mac windows.