This will respect the official build configuration where we should
have BLOSC enabled.
We can't really detect if OpenVDB was compiled with BLOSC or not,
so seems we can't really avoid this extra flag.
D1751, remove this library since its quite a specific - only supports an older version of this codec.
Also ffmpeg has added support for recent versions of the codec.
This commit makes sure Linux and Windows buildbots are using OpenSubdiv
and also enables OpenSubdiv by default on Windows.
OSX is kept disabled still, this is due to OpenGL restrictions which are
not solved in any way yet.
Linux is defaults to OpenSubdiv disabled because it needs precompiled
library.
The documentation could be found there:
http://wiki.blender.org/index.php/User:Nazg-gul/OpenSubdiv
