regenerated documentation

tagging version v3.6.0-alpha.0

minor changelog update

bugfix in linux RPM package generation

Merge branch 'embree_api_namespace' into devel

added gcc4.7 and gcc4.1 hint for finding TBB user linux

updated version to v3.5.1-alpha.1

Fixed self intersection avoidance for ray oriented discs when non-nor…

…malized rays were used.

disabled BVH8 on Skylake server CPUs

updated documentation