Problems with lighting of extruded custom-shapes

[Regina Henschel]

Hi Miklos,

I have put it into code now, see 
https://gerrit.libreoffice.org/c/core/+/128449
That makes it perhaps easier to discuss the problems.

My changes give good results for import of MS binary formats, especially 
if the user has chosen to illuminate the object from front or if the 
user had set surface 'Metal' in the UI of MS Office. I can sent you 
files in MS binary format for testing. But I think you will already have 
got lots of those files.

The code is WIP and the unit tests from my previous commit will break. 
But the code itself builds here on Windows, so you should be able to 
build a working version for testing.

Kind regards,
Regina