* Add WITH_BF_YAFRAY, which per default is 'true', so no visible changes for developers (and users).
Set WITH_BF_YAFRAY to 'false', and you'll save some major compile time :) Also handy if you're strapped for memory and compilation fails on yafray compilation due
to this.
- this commit also has a few whitespace changes and
- made BF_NO_ELBEEM a proper BoolOption. This will be renamed to WITH_BF_ELBEEM in the near future...